# Limits and functions

• September 26th 2010, 05:49 PM
tofuwrice
Limits and functions
Okay I have 2 questions.

If $f(x)=2x^2+3x+5$

Find
https://newton.science.sfu.ca/cgi-bi...0%29%7D%7Bh%7D

and

If
$

f(x)=-(25/2x+3)

$

Find

https://newton.science.sfu.ca/cgi-bi...1%29%7D%7Bh%7D

A 2
B 3
C +infinity
D 1
E Does Not Exist
F 0
G 4
H None of the above

I've tried and asked my friends and no one knows how to start this.
• September 26th 2010, 06:29 PM
mr fantastic
Quote:

Originally Posted by tofuwrice
Okay I have 2 questions.

If $f(x)=2x^2+3x+5$

Find
https://newton.science.sfu.ca/cgi-bi...0%29%7D%7Bh%7D

[snip]

Start by getting an expression for f(h). Then get f(0). Then get f(h) - f(0) and simplify. Then divide the result by h. Then take the limit. Alternatively, recognise the value of the limit as f'(0).

Quote:

Originally Posted by tofuwrice
[snip]
If
http://www.mathhelpforum.com/math-he...2ee2fd7331.png

Find

https://newton.science.sfu.ca/cgi-bi...1%29%7D%7Bh%7D