Question

Tan²x = + 1 ,

Answer 1

tan²x = 1/cosx + 1 , 0<x< 2π

sin²x = cos x+ cos²x , 0<x< 2π

cos x+cos²x-sin²x =0 , 0<x< 2π

cos²x +cos x- (1-cos²x) =0 , 0<x< 2π

cos²x +cos x- 1+cos²x) =0 , 0<x< 2π

2cos²x +cos x- 1 =0 , 0<x< 2π

(2cosx -1)(cos x+1) =0 , 0<x< 2π

2cosx1 -1=0

2cosx1 =1

cosx1 =½

x1=π/3 ; 5/3 π

cosx2 + 1=0

cosx2 =-1

x2=π;