Derive these identities using the addition or subtraction formulas for sine or cosine:

a. sin a sin b = 1 / 2(cos(a – b) – cos(a + b))

b. sin a cos b = 1 / 2(sin(a + b) + sin(a – b))

Step-by-step explanation:

cos(a-b)-cos(a+b)=2(sina x sinb)

using formulae of cos (a-b) & cos(a+b)

cos a cos b + sina sinb - cosa cosb + sina sinb=2 sina sinb

2 sina sinb = 2 sina sinb

proved!

logv3(x+2)=1

rewrite in exponential form:

logb(x) = y is equal to b^y =x

b = 3, y = 1

now solve for x:

3^1 = x+2)

x = 3-2

x = 1

see the picture for the graph.

answer:

your answer is: c. 196 7/8 in^3.