Hao123 Pro: Lượng giác

<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBaP9Xlsk3BsOjx2E3l2I6yXTMhdQ0k5Y2ydCwPsKzsuAQDI11CUtPx2XieJMGt42zTeeRegOOdoELYU4lYjHltHJ0Xo7BXL7KvLH2JCRNnC66_UMH93bJkoWafMAV_GbiWefhXck_cMo/s1600/32.jpeg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="277" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBaP9Xlsk3BsOjx2E3l2I6yXTMhdQ0k5Y2ydCwPsKzsuAQDI11CUtPx2XieJMGt42zTeeRegOOdoELYU4lYjHltHJ0Xo7BXL7KvLH2JCRNnC66_UMH93bJkoWafMAV_GbiWefhXck_cMo/s400/32.jpeg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><h2><span style="font-size: small;"><span style="font-weight: normal;"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;">Nhớ gọn công thức lượng giác trong tích tắc</span></span></span></span></h2></td></tr></tbody></table><h2 style="text-align: center;"><span style="font-weight: normal;"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"></span></span></span><span style="color: #38761d;"></span><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Bye bye nỗi sợ đi vì bọn tớ mách nước cho rồi!</span></span></span><span style="font-family: Times,"Times New Roman",serif;"></span></h2><span style="color: #38761d;"></span><div class="lead"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"> </span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">                                         	</span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Công thức lượng giác là công cụ  đầu tiên để bạn xử lí rất rất nhiều bài tập toán học. Ấy thế nhưng, nó  lại nhiều quá, dài quá, khiến không ít teen vã mồi hôi hột để học thuộc  mà vẫn thường xuyên nhầm lẫn. Dành khoảng 20 phút cùng <a href="http://dongluccuocsong.vn/">dongluccuocsong.vn</a> xem mọi thứ dễ dàng  đi nhiều nhé:</span></span></span></div><div class="Normal"><br /></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">• Sin= đối/ huyền</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Cos= kề/ huyền</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Tan= đối/ kề</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Cot= kề/ huyền</span></span></span></div><div class="Normal"><br /></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">♥Thần chú: Sin đi học, Cos không hư, tan đoàn kết, cotan kết đoàn</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Hoặc: Sao đi học, cứ khóc hoài, thôi đừng khóc, có kẹo đây!</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><br /></div><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">• Công thức cộng:</span></span></span></div><div class="Normal"><br /></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Cos(x y)= cosxcosy sinxsiny</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Sin(x y)= sinxcosy cosxsiny</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">♥Thần chú: Cos thì cos cos sin sin</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Sin thì sin cos cos sin rõ ràng</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Cos thì đổi dấu hỡi nàng</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Sin thì giữ dấu xin chàng nhớ cho!</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Tan(x+y)=  </span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><br /></div><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Thần chú: Tan một tổng hai tầng cao rộng</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Trên thượng tầng tan cộng cùng tan</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Hạ tầng số 1 ngang tàng</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Dám trừ đi cả tan tan oai hùng </span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Hoặc: Tang tổng thì lấy tổng tang</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Chia một trừ với tích tang, dễ òm.</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><br /></div><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">• Công thức biến đổi tổng thành tích:</span></span></span></div><div class="Normal"><br /></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Ví dụ: cosx+cosy= 2cos cos </span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">  (Tương tự những công thức như vậy)</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">♥ Thần chú: cos cộng cos bằng 2 cos cos</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Cos trừ cos bằng 2 sin sin</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Sin cộng sin bằng 2 sin sin</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Sin trừ sin bằng 2 cos sin.</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">* Tan ta cộng với tan mình bằng sin hai đứa trên cos mình cos ta.</span></span></span></div><div class="Normal"><br /></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody><tr><td style="text-align: center;"><img alt="study5-263194-1371431206_500x0.jpg" border="1" height="353" src="http://l.f20.img.vnecdn.net/2011/04/11/study5-263194-1371431206_500x0.jpg" style="margin-left: auto; margin-right: auto;" width="400" /></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="color: purple;"><span style="font-size: small;"><span style="font-size: large;">See you at the Top</span></span></span></td></tr></tbody></table><div align="center" class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><br /></div><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">• Công thức biến đổi tích thành tổng:</span></span></span></div><div class="Normal"><br /></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Ví dụ: cosxcosy=1/2[cos(x+y)+cos(x-y)] (Tương tự những công thức như vậy)</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Thần chú: Cos cos nửa cos-cộng, cộng cos-trừ</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Sin sin nửa cos-trừ trừ cos-cộng</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Sin cos nửa sin-cộng cộng sin-trừ.</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><br /></div><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">• Công thức nhân đôi:</span></span></span></div><div class="Normal"><br /></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Ví dụ: sin2x= 2sinxcosx (Tương tự những công thức như vậy)</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Thần chú: Sin gấp đôi = 2 sin cos</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Cos gấp đôi = bình cos trừ bình sin</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">  = trừ 1 cộng hai bình cos </span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">  = cộng 1 trừ hai bình sin </span></span></span></div><div class="Normal"><br /></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">(Chúng mình chỉ việc nhớ công thức nhân đôi của cos bằng thần chú trên rồi từ đó có thể suy ra công thức hạ bậc.)<br />Tang gấp đôi=Tang đôi ta lấy đôi tang (2 tang)</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Chia 1 trừ lại bình tang, ra liền.</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><br /></div><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">• Hàm số lượng giác và các cung có liên quan đặc biệt:</span></span></span></div><div class="Normal"><br /></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Ví dụ: Cos(-x)= cosx</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Tan( + x)= tan x</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Thần chú: Sin bù, Cos đối,Tang Pi,</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;">Phụ nhau Sin Cos, ắt thì phân chia</span></span></span></div><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"></span></span></span><div class="Normal"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"> Hoặc : Cos đối, sin bù, phụ chéo, hơn kém pi tang .</span></span></span></div><div class="Normal"><br /></div><div class="Normal" style="text-align: right;"><span style="color: #38761d;"><span style="font-family: Times,"Times New Roman",serif;"><span style="font-size: large;"><span style="color: purple;"><span style="font-family: Verdana,sans-serif;"><b><i>Sưu tầm</i></b></span></span> </span></span></span></div>

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