答案见上解析 若$$ \alpha = \frac { \pi } { 6 } , \beta = \frac { 5 \pi } { 6 } $$,则满足$$ \sin \alpha = \sin \beta $$,而不满足$$ \alpha = \beta $$;当 $$ \alpha = \beta $$时,$$ \sin \alpha = \sin \beta $$一定成立,所以“$$ \sin \alpha ...
证明: $$ \sin ( \alpha + \beta ) = \cos \left[ - ( \alpha + \beta ) + \frac { \pi } { 2 } \right] \\ = \cos \left[ ( - \alpha + \frac { \pi } { 2 } ) - \beta \right] \\ = \cos ( - \alpha + \frac { \pi } { 2 } ) \cos \beta + \s...
If cos(alpha + beta) = 3/5, sin(alpha - beta) = 5/13 And 0 lt alpha, beta lt pi/4 , Then tan(2alpha) Is equal If0<α,β<π/4,cos(α+β)=4/5,sin(α−β)=5/13thentan2α= View Solution मानाcos(α+β)=45औरमाना(α−β)=513जह...
Ifcos(α+β)=45andsin(α−β)=513, whereαlie between 0 andπ4, then find that value oftan2α. β)=45,sin(α−β)=513,0<αβπ4thentan2α= ……… If cos(alpha+beta)=4/5; sin(alpha-beta)=5/13 and alpha,beta lie between 0π/4 then find the value of tan2alpha If...
Answer to: Find the exact value of cos (alpha + beta) if sin alpha = 3 / 5 and sin beta = {12} / {13}, with alpha in quadrant I and beta in...
【解析】 [分析一] 条件中易解出$$ A = \frac { \sin a } { \sin ( \alpha + \beta ) } $$,再代入求证式的右边. [证一] 当$$ \sin ( \alpha + \beta ) \neq 0 $$时,$$ A = \frac { \sin \alpha } { \sin ( \alpha + \beta ) } $$,于是 $$ \frac { \sin \b...
【题目】8.证明:(1)$$ \sin ( \alpha + \beta ) \sin ( \alpha - \beta ) = \sin ^ { 2 } \alpha - \sin ^ { 2 } \beta $$(2)$$ \cos ^ { 2 } x + \cos ^ { 2 } ( \frac { 2 \pi } { 3 } + x ) + \cos ^ { 2 } ( \frac { 4 \pi } { 3 } +...
alpha, betaలు పూరక కోణాలు, b sin alpha =a అయితే, (sin alpha cos beta - cos alpha sin beta)విలువను కనుక్కోంది.
Let alpha,beta be such that pi lt alpha-beta lt3 pi. If sin alpha+ sin beta=(-21)/65 and cos alpha+ cos beta=(-27)/65, then the value of cos((alpha-beta)/2) i
Answer to: Determine whether the below statement is true or false. cos(alpha - beta) = cos alpha cos beta + sin alpha sin beta a. True b. False By...