# derivate

• Feb 17th 2010, 03:50 PM
wannous
derivate
If http://gauss.vaniercollege.qc.ca/web...a81e0309b1.png, find http://gauss.vaniercollege.qc.ca/web...d85b323ce1.png.

f(x) = 4x + 2x^-1

f ' (x) = 4 - 2x^-2 = 4 - 2/x^2

can anybody tell me what im doing wrong?
• Feb 17th 2010, 04:00 PM
danielomalmsteen
$y=4x+\frac{2}{x}$

then

$y' = 4+2\cdot \left(\frac{1}{x} \right)'$

Now using the quotient rule

$y'=4-2 \cdot \left(\frac{1}{x^2} \right)$

can now conclude
• Feb 17th 2010, 04:04 PM
wannous
thank you my good sir