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Monday, March 3, 2014

Second Derivative Problems - Chain Rule

Category: Differential Calculus, Algebra

"Published in Newark, California, USA"

If y = f(u) and u = ϕ(x), show that 


Solution:

Consider the given two equations above



Since y is a function of u and u is a function of x, then we can apply the derivative of y with respect to x by Chain Rule Method.

Take the derivative of the first equation with respect to u, we have



Take the derivative of the second equation with respect to x, we have



Hence, by Chain Rule Method,



Take the derivative of the above equation with respect to x, we have










but


Hence, the above equation becomes





Therefore,


where





Sunday, March 2, 2014

Second Derivative Problems - Reciprocal Formula

Category: Differential Calculus, Algebra

"Published in Vacaville, California, USA"

Using the fact that


show that


Solution:

Consider the given equation above


Take the derivative on both sides of the equation with respect to x by quotient formula, we have










Therefore,


Saturday, March 1, 2014

Second Derivative Problems - Quotient Formula

Category: Differential Calculus, Algebra

"Published in Vacaville, California, USA"

Find a formula for


Solution:

The first thing that we have to do is to get the derivative of u/v with respect to x where u and v are functions of x. Apply the derivative by quotient formula, we have 




Take the derivative again of the above equation with respect to x by product formula, we have






 






where: