阅读下面材料:根据两角和与差的正弦公式,有sin(a+B)sin a cos 8+cos a sin B ----------①sin(a-B)=sin a cos B-cos asin B ------②由①+② 得sin(a+B)+sin (a-B)=2 sin acos B ------③令a+B=Aa-B= B 有A+B A-B=22代入③得 A+B A-B sin A+sin
【题目】三角函数中,有两个常用的公式:(1)$$ \sin ( \alpha + \beta ) = \sin \alpha \cos \beta + \cos \alpha \sin \beta $$(2)$$ \cos ( \alpha + \beta ) = \cos \alpha \cos \beta - \sin \alpha \sin \beta $$求sin$$ 7 5 ^ { \circ } $$的值. ...
Delta=|{:(" "0,sin alpha,-cos alpha),(-sinalpha," "0,sin beta),(cos alpha,-sinbeta," "0):}| का मान ज्ञात कीजिए
2.两角差的正弦、余弦、正切公式(1)$$ ) \sin \alpha \cos \beta - \cos \alpha \sin \beta = \sin ( \alpha - \beta ) $$(2)$$ \cos \alpha \cos \beta + \sin \alpha \sin \beta = \cos ( \alpha - \beta ) . $$(3)$$ \frac { \tan \alpha - \tan \beta } { 1 ...
两角和与差的余弦、正弦、正切公式.(1)\cos \left(\alpha -\beta \right)=\cos \alpha \cos \beta +\sin \al
题目 (2)两角和与差的正弦公式$$ \sin ( \alpha + \beta ) = \_ \_ \_ \sin \alpha \cos \beta + \cos \alpha \sin \beta $$$ \sin ( \alpha - \beta ) = \_ \sin \alpha \cos \beta - \cos \alpha \sin \beta $$ 相关知识点: 试题来源: 解析 答案见上 反馈 收...
【题目】1.两角和与差的余弦、正弦、正切公式$$ \cos ( \alpha - \beta ) = \cos \alpha \cos \beta + \sin \alpha \sin \beta ( C _ { ( \alpha - \beta ) } ) $$$ \cos ( \alpha + \beta ) = \_ ( C _ { ( \alpha + \beta ) } ) $$$ \sin ( \alpha - \beta ) ...
1.两角和与差的正弦、余弦和正切公式$$ \sin ( \alpha \pm \beta ) = \sin \alpha \cos \beta \pm \cos \alpha \sin \beta ; $$$ \cos ( \alpha + \beta ) = \cos \alpha \cos \beta \pm \sin \alpha \sin \beta ; $$$ \tan ( \alpha \pm \beta ) = \frac { \tan \...
7.若$$ \sin ( \alpha + \beta ) + \cos ( \alpha + \beta ) = 2 ( \sin \alpha - \cos \alpha ) \sin \beta = \frac { 2 } { 3 } $$,则$$ \sin ( 2 \alpha - 2 \beta ) = $$ A.$$ \frac { 7 } { 9 } $$ B.$$ \frac { 1 } { 9 } $$ C.-$$ ...
【题目】若角α和β的终边关于_y轴对称,则下列各式中正确的是()$$ A . \sin \alpha = \sin \beta $$$ B . \cos \al