Thursday

July 31, 2014

July 31, 2014

Posted by **Dee** on Monday, February 26, 2007 at 10:52am.

Differentiate

f(x)=(5x-4)^2

There are two ways to do this:

(1) let u = 5x-4, and use the "chain rule", df/dx = df/du * du/dx

OR

(2) expand the polynomial to

f(x) = 25 x^2 -40x + 16

and differentialte it term-by-term.

You will get the same answer either way.

Let's use the first way, because it is something you may need for other problems

u = 5x-4

du/dx = 5

f(u) = u^2

df/dx = df/du * du/dx

= 2 u * 5 = 10(5x -4) = 50x - 40

**Related Questions**

calculus - I have been asked to solve this two different ways. The first way is...

Calculus - I'm having problems with this one. Can't get the right answer. ...

Calculus - How do I use the chain rule to find the derivative of square root(1-x...

calculus - I am having trouble with this problem also derivative differentiate f...

Math, Calculus - Find the derivative of the function. y= xcosx - sinx What's the...

calculus - Please help. Applying the chain rule, how do I find the derivative of...

Calculus - Can anyone explain how to use the chain rule and power rule together ...

Differentiation - How do you find f'(x), f''(x) of f(x) =ln (1-x) IF f(x) = ln (...

Math - Calculus Question. - hey can someone explain to me the relationship ...

MoRe HeLp PlEaSe!! (calc) - Also can I get some help with this LONG, TIRESOME ...