sin \beta $$,其$$ \beta \in R $$,简记作$$ S _ { ( \alpha + \beta ) } $$;(3)两角差的正弦公式$$ i n ( \alpha - \beta ) = \sin \alpha \cos \beta - \cos \alpha \sin \beta , $$,其中α,$$ \beta \in R $$,简记作 $$ S _ { ( \alpha - \beta ) } ...
1.两角和与差的余弦、正弦、正切公式(1)公式$$ C _ { ( \alpha - \beta ) } : $$$ \cos ( \alpha - \beta ) = \cos \alpha \cos \beta + \sin \alpha \sin \beta $$(2)公式 $$ C _ { ( \alpha + \beta ) } $$:$$ \cos ( \alpha + \beta ) = \cos \alpha \...
beta ) } : \tan ( \alpha - \beta ) = \frac { \tan \alpha - \tan \beta } { 1 + \tan \alpha \tan \beta } $$(6)公式$$ C _ { ( \alpha + \beta ) } : \tan ( \alpha + \beta ) = \frac { \tan \alpha + \tan \beta } { 1 - \tan \alpha \tan \beta...
(5)公式$$ T _ { ( \alpha - \beta ) } : \tan ( \alpha - \beta ) = \frac { 1 } { 1 + \tan \alpha \tan \beta } $$___;(6)公式$$ T _ { ( \alpha + \beta ) } : \tan ( \alpha + \beta ) = \frac { \tan \alpha + \tan \beta } { 1 - \tan \al...
y+ \sin x \sin y( $$② 由$$ \textcircled{1}+ \textcircled{2}得 $$ ③ $$ \cos(x+y)+ \cos x \cos y( $$ 令$$ \alpha=x+y \beta=x-y $$ ,将x,β代入③得 $$ \cos \alpha + \cos \beta =2 \cos \frac{\alpha + \beta}{2} \cos \frac{\alpha - \beta}{2} $...
两角和与差的正弦、余弦、正切公式$$ C _ { ( \alpha + \beta ) } : \cos ( \alpha + \beta ) = \cos \alpha \cos \beta - \sin \alpha \sin \beta $$$ C _ { ( \alpha - \beta ) } : \cos ( \alpha - \beta ) = \_ $$$ S _ { ( \alpha + \beta ) } : \s...
两角和与差的正弦、余弦公式 $$ \cos ( \alpha + \beta ) = \cos \alpha \cos \beta - \sin \alpha \sin \beta $$. $$ \cos ( \alpha - \beta ) = \cos \alpha \cos \beta + \sin \alpha \sin \beta $$. $$ \sin ( \alpha + \beta ) = \sin \alpha \cos \beta + ...
( \alpha - \beta ) \right] \\ \frac { 1 } { 2 } \left[ \sin ( \alpha + \beta ) - \sin ( \alpha - \beta ) \right] \\ 2 \sin \frac { x + y } { 2 } \cos \frac { x - y } { 2 } $$ $$ 2 \cos \frac { x + y } { 2 } \sin \frac { x -...
1.两角和与差的余弦、正弦、正切公式(1)公式$$ C _ { \alpha - \beta } : \cos ( \alpha - \beta ) = \cos \alpha \cos \beta + \sin \alpha \sin \beta $$___;(2)公式$$ C _ { \alpha + \beta } : \cos ( \alpha + \beta ) = \cos \alpha \cos \beta - \sin ...
1两角和与差的正弦、余弦、正切公式$$ C _ { ( \alpha + \beta ) } : \cos ( \alpha + \beta ) = \cos \alpha \cos \beta - \sin \alpha \sin \beta . $$$ C _ { ( \alpha - \beta ) } : \cos ( \alpha - \beta ) = \cos \alpha \cos \beta + \sin \alpha \sin \be...