y=cos^2(x^2-x)求导,答案是-2cos(x^2-x)sin(x^2-x)(2x-1)
问题描述：
y=cos^2(x^2-x)求导,答案是-2cos(x^2-x)sin(x^2-x)(2x-1)
答
y=cos²(x²-x)
y'=2cos(x²-x)×[cos(x²-x)]'×(x²-x)'
y'=2cos(x²-x)[-sin(x²-x)](2x-1)
y'=2(1-2x)sin(x²-x)cos(x²-x)麻烦解释一下第一步到第二步？复合函数求导法则：假设f(g(x))是一个复合函数，其求导法则是：f'(g(x))=[f(g(x))]'·g'(x)