Find the value of this expression: sin 45 sin 15 . the second step = a. 1 sin 60 – sin 30 2 b. 1 cos 60 cos 30 2 c. 1 sin 60 sin 30 2 d. 1 cos 60 cos 30 find the value of this expression: cos 75 – cos 15 . the second step = a. –2 cos 45 cos 30 b. –2 sin 45 sin 30 c. 2 sin 45 cos 30 d. 2 cos 45 sin 30

Given expression is sin(45)sin(15)

this expression best matches with left side of the formula:

2 sin(A) sin(B)= cos(A-B) - cos(A+B)

so we can plug given angles 45 and 15 there

2 sin(45) sin(15)= cos(45-15) - cos(45+15)

2 sin(45) sin(15)= cos(30) - cos(60)

sin(45) sin(15)= [cos(30) - cos(60)]/2

We are getting negative sign and cos in the solution while none of the given choices have same situation so answer will be none of them.

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For cos(75)-cos(15), we will use formula:

Now plug the given angles

Hence choice B is correct.

i think c. but don't trust it.

step-by-step explanation:

answer: ♡♡♡♡♡♡♡♡♡♡

step-by-step explanation: