Question

If cos x = sin(20 + x)° and 0° < x < 90°, the value of x is ?

Answer 1

well:
90 - x - 20 = x
combine like terms
70-x=x
add x to each side
2x = 70
divide by 2 for each side
x = 35

to check:
cos(35)=.8
sin(35+20)=.8

there we are :)
x=35 :)

Answer 2

thanks <3

Answer 3

my pleasure :)