Math Is Fun Forum

steve00000

Guest

proof d/dx sinx = cos du/dx

Ive been having problems trying to understand the difference between a differential and a derivative.

the derivative of cosx = - sinx and i can proof this using  the basic derivative forumula.

but how would i do the same thing to proof the differential?

Thanks

George,Y

Member

Registered: 2006-03-12

Posts: 1,379

Re: proof d/dx sinx = cos du/dx

you just proved
Δ(Cosx)/Δx=-Sinx+o(Δx)
where o(Δx)/Δx->0 thus neglective

So you have proved
d(Cosx)/dx=-Sinx
According to Leibniz's definition
This can be called as
d(Cosx)=-Sinx*dx               -  differential form

---

X'(y-Xβ)=0