Hello bullyluver2009

Welcome to Math Help Forum! Originally Posted by

**bullyluver2009** I don't understand how to do differentiation or to find the equation of the line tangent to the graph at the point. Could someone please help me with a few homework questions I have?

Consider the following:

Use the power rule for differentiation to find

*f* '(

*x*). Give your answer using the form below where

*B* >

*D* >

*F*.

*f* '(

*x*) =

*Ax^B* +

*Cx^D* +

*Ex^F*
It asks what A-F equals. I have no clue where to even start with this question.

The next question is Find the equation of the line that is tangent to the graph of

*f*(

*x*) = 2

*x^*4 - 7

*x^*2 + 230 at the point (3, 329).

y(x)=?

Ok and one more please

*Consider the following: f*(

*x*) = 3

*x^*2 - 7

*x* Find f(7)...I thought you would just put 7 in where x is but that answer did not work

I would appreciate any help!

Although it may not seem like it, these are really very basic questions on differentiation, so you need to review any notes and examples that you've been given.

The basic rule is: If $\displaystyle f(x) = ax^n$, then $\displaystyle f'(x) = nax^{n-1}$

In other words:Multiply by the power, and then decrease the power by $\displaystyle 1$.

This applies to fractional as well as integer powers, so, for example:$\displaystyle f(x) = 4x^{\frac45} \Rightarrow f'(x) = \frac{16x^{-\frac15}}{5}$

Maybe you will also need to review the meaning of fractional powers; for example, $\displaystyle \sqrt x = x^{\frac12}$. So $\displaystyle f(x) = \sqrt x \Rightarrow f'(x) = \frac{1}{2\sqrt x}$.

Grandad