【题目】给出下列式子:【题目】给出下列式子: \$\cos ( \alpha - \beta ) = \cos \alpha - \cos \beta\$ 【题目】给出下列式子: \$\cos ( \alpha - \beta ) = \cos \alpha - \cos \beta\$ 【题目】给出下列式子:【题目】给出下列式子:【题目】给出下列式子:【题目】给出下列式子:...
相关知识点: 试题来源: 解析 【解析】 【解析】 【解析】 【解析】 【解析】 \$\sin \alpha - \sin \beta = - \frac { 1 } { 3 } \cos \alpha - \cos \beta = \frac { 1 } { 2 }\$ 两边平方相加 反馈 收藏
cos(α-β) 的值. 相关知识点: 试题来源: 解析 【答案】(1);(2) 【解析】【分析】(1)展开与,求出与的值,即可计算的值;(2)利用完全平方公式及两角差的余弦公式,即可求出的值.【详解】解:(1)由题意,,,(2)把两边分别平方得把两边分别平方得,把所得两式相加,得,即,所以.【点睛】本题考查...
关于三角函数有如下的公式:\cos (\alpha - \beta )= \cos \alpha \cos \beta \sin \alpha \sin \beta,由该公式可求得\cos 15^ \circ的值是() A. { \sqrt 6+ \sqrt 2}\div 4\ \ B. { \sqrt 6- \sqrt 2}\div 4\ \ C. { \sqrt 3- \sqrt 2}\div 4\ \ D. { \sqrt 3\ ...
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解得:cos\beta =\dfrac{-1\pm \root \of {7} }{4},sin\beta =\dfrac{1\pm \root \of {7} }{4}所以:sin\alpha =\dfrac{-1\pm \root \of {7} }{4},cos\alpha =\dfrac{1\pm \root \of {7} }{4}所以sin(\alpha +\beta )=sin\alpha cos\beta +sin\beta cos\alpha 代入上...
Step by step video, text & image solution for If cos (alpha - beta) + cos (beta - gamma) + cos (gamma - alpha) = (-3)/(2) then prove that cos alpha + cos beta+ cos gamma = sin alpha + sin beta + sin gamma = 0. by Maths experts to help you in doubts & scoring excell...
Step by step video & image solution for सिद्ध कीजिए की cos alpha+cos beta+cos gamma+cos (alpha+beta+gamma)= 4cos (alpha+beta)/2cos""(beta+gamma)/2cos""(gamma+alpha)/2 by Maths experts to help you in doubts & scoring excellent marks in Class 11 ...
题目:若\( \cos(\alpha + \beta) = \cos\alpha \cos\beta - \sin\alpha \sin\beta \),那么\( \sin(\alpha + \beta) = ___ 。相关知识点: 试题来源: 解析 答案:\( \sin\alpha \cos\beta + \cos\alpha \sin\beta \) 反馈 收藏
{1 - \tan \alpha \ast \tan \beta }③利用这些公式可将某些不是特殊角的三角函数转化为特殊角的三角函数来求值,如:\tan 105^{{\circ} }=\tan (45^{{\circ} }+ 60^{{\circ} }) = \dfrac{\tan 45^{{\circ} } + \tan 60^{{\circ} }}{1 - \tan 45^{{\circ} }\ast \tan 60...