y=sinx^3,则dy/d(x^2)=

dy = 3x^2 cos x^3 dx
d(x^2) = 2x dx
dy/d(x^2) = 3x^2 cosx^3 dx/(2x dx) = 3x^2 cosx^3 /2x = 1.5x cos x^3

Y = cos2x +氮化硅= 1-2（氮化硅）^ 2 + sinx的= -2 [氮化硅 - 1/4] ^ 2 + 9/8，点击看详细，因为-1≤sinx≤1


所以取最大值9/8时，氮化硅= 1/4，到时采取的SiNx = -1 -2点击看详细最小的范围内，从而[ - 2,9 / 8]