求导,高数,dy/dx什么含义?跟y'有什么关系?(d²y)/(dx²)是不是代表y''?(d²y)/(dx²)和(d²y)/(d²x)的区别?

求导,高数,dy/dx什么含义?跟y'有什么关系?(d²y)/(dx²)是不是代表y''?(d²y)/(dx²)和(d²y)/(d²x)的区别?
求导,高数,

dy/dx什么含义?跟y'有什么关系?(d²y)/(dx²)是不是代表y''?(d²y)/(dx²)和(d²y)/(d²x)的区别?

求导,高数,dy/dx什么含义?跟y'有什么关系?(d²y)/(dx²)是不是代表y''?(d²y)/(dx²)和(d²y)/(d²x)的区别?
dy/dx=(-2/sintcost)/(sect)^2=-2cost/sint=-2cot t
故：d^2y/dx^2=2(csct)^2
将t=π/6代入,等于8
dy/dx是y'.(d²y)/(dx²)代表y''.没有(d²y)/(d²x）.