Sec inverse of 2 = x. Meaning it is asking
"Where is sec equal to 2?" Well, sec is one over cos, so we essentially want to know when cos is 1/2. Between 0 and 360 degrees, cos is 1/2 at 60 and 300 degrees.
So your answer is x = 60, and 300
Sin2x=cosx
Use the identity for Sin2x to get:
2sinxcosx = cosx
Now move the cosx over to get:
2sinxcosx-cosx = 0
Take out the greatest common factor:
Cosx(2sinx-1) = 0
Now solve with each individual part.
Cosx= 0
X = 90 and 270 degrees.
2sinx-1 = 0
2Sinx = 1
Sinx = 1/2
X= 30 and 150 degrees.
I hope this Helps!