algebra
posted by ken on .
given that sin (2x+30)=cos(x15).determine the value of x given x is an acute angle

assuming that x is in degrees, then knowing that cos(x) = sin(90x), we have
sin(2x+30) = sin(90(x15))
sin(2x+30) = sin(105x)
so,
2x+30 = 105x
3x = 75
x = 25
check:
sin(80) = cos(10)
yep.