Question

Find the value of x for the pair of acute angles that corresponds to the solution of the equation: sin(3x + 2) = cos(7x + 8).

a
x = 10
b
x = 8
c
x = 4
d
x = -1.5

Answer 1

x = 8

Explanation:

3x + 2 + 7x + 8 = 90

10x + 10 = 90

10x = 80

x = 8

Check: 3x + 2 = 3(8) + 2 = 26°

7x + 8 = 7(8) + 8 = 56 + 8 = 64°

sin 26 = cos 64