fiind all solutions at interval [0,2pi] sin^2x - cos^2x = 0

Question

 find all the solutions at the interval [0,2pi] for the equation sin^2 x - cos^2 x = 0

Answer 1

0 = sin^2 - cos^2

   = sin^2 - ( 1 - sin^2)

  = sin^2 - 1 + sin^2 

  = 2sin^2 - 1

 

 

 sin^2 = 1/2

 

 sin = +or- sqrt(2)/2

 

 

X= 45, 135, 215, 315 degrees