Do you have to use double angle identies Or can you just loo

Do you have to use double angle identies? Or can you just look for x when tan is 1 for 0 degrees to 360? ...which would be 45 and 225 degrees..... ?

Oh then divide by 2.... to get back to 0 to 180..

sin2x = cos2x

divide both sides by cos2x

sin2x/cos2x = cos2x/cos2x

tan2x =1

2x = tan^-1(1)

2x = k*pi +pi/4

General Solution : x = ( 4k*pi +pi)/8

k =0 ; x = pi/8

k=1 ; x = 5pi/8

k =2 ;x = 9pi/8

pi/8 , 5pi/8 , 9pi/8 , 13pi/8

For 0<=x<=180 valid solutions are ( pi/8 , 5pi/8 ) ie. ( 22.5 , 112.5 deg)