1) f'= e^-x^2*(-2x) f"=e^-x^2*(-2x)*(-2x)+e^-x^2*(-2)=e^-x^2*4x^2-2*e^-x^2 2) f'=1/(sin^2 x) f"= (0-1*2cos x)/sin^4 x 3) f'=-2sin x f"=-2cos x