Verify the identity. Show your work.
cos(α - β) - cos(α + β) = 2 sin α sin β

my answercos=o

Question

Verify the identity. Show your work.
cos(α - β) - cos(α + β) = 2 sin α sin β 

my answer>cos=o

anonymous · Answer

Teacher:Use the sum and difference formulas for this
me:wtf you mean

anonymous · Answer

@misty1212

sohailiftikhar · Answer

cos(a-b)=cos(a)cos(b)+sin(a)sin(b)
cos(a+b)=cos(a)cos(b)-sin(a)sin(b)
these are the formulas

anonymous · Answer

woow ok so do i use both of them or what

sohailiftikhar · Answer

you have both terms cos(a-b) and cos(a+b) so use both

sohailiftikhar · Answer

in this problem

anonymous · Answer

ok so this is a practice question imma gonna be graded on so can you help me plz

sohailiftikhar · Answer

ok

anonymous · Answer

2cos(A)cos(B)=2cos(A)cos(B) ok so i got this instead is this right

anonymous · Answer

@misty

sohailiftikhar · Answer

no it's not right

sohailiftikhar · Answer

ok i'm going to solve it

sohailiftikhar · Answer

$$\cos(\alpha-\beta)-\cos(\alpha+\beta)=(\cos \alpha \cos \beta +\sin \alpha \sin \beta)-(\cos \alpha \cos \beta -\sin \alpha \sin \beta )$$

sohailiftikhar · Answer

now $$\cos \alpha \cos \beta +\sin \alpha \sin \beta -\cos \alpha \cos \beta +\sin \alpha \sin \beta =2 \sin \alpha \sin \beta $$