siny+xy-x^3=2,求y''.
问题描述:
siny+xy-x^3=2,求y''.
是求y
答
siny+xy=2+x^3两边导数cosy*y′+y+xy′=3x^2y′(cosy+x)+y=3x^2 (1)y′=(3x^2-y)/(cosy+x) (2)对(1)两边求导y''(cosy+x)+y′(-sinyy′+1)+y′=6xy''(cosy+x)+y′(-sinyy′+2)=6xy''=[6x+siny(y′)² +...