Show that the min value of 4x2+4x |sin@| - cos2@ is -1

hi,

p = 4x²+4x |sin@| -  cos²@  is -1

   = 4x²+4x |sin@| -1 + sin²@                 (  sin²@  = |sin@| ^2 )

   =4x²+4x |sin@| + |sin@| ^2 - 1

   = ( 2x + |sin@| )^2  -1

 give min . value when the squre part will be equal to zero.

 hence min. value = -1