Question

sin x = cos (3x + 20)

Answer 1

Answer:

$x=17.5^o$

Step-by-step explanation:

The question is

Find the value of x

we know that

If  sin(A)=cos(B)

then

angle A and angle B are complementary angles

so

$A+B=90^o$

In this problem

$sin(x)=cos(3x+20)$

so

$x^o+(3x+20)^o=90^o$

solve for

$4x+20=90$

$4x=90-20$

$4x=70$

$x=17.5^o$