Maximum value and minimum value of f(x)=4(sin^2x+cos^4x)?please provide detailed answer soon,would be grateful.......

I am writing theta as x as there is no theta symbol in my keyboard Now on differentiating the function with respect to X we getF`(x)=8sinxcosx-16cos³xsinx F`(x)=8sinxcosx(1-cos²x)For max or min valueF`(x)=0=>8sinxcosx(1-cos²x)=0=> which gives us the value that either either x=0 or x=[π\2] and double differentiate to check the maxima and minima Hope it helps and if u r a girl it would be a pleasure if u give your no. HahaLOLz just kidding