Series Expansion

**Haris** · January 26th 2009, 08:53 AM

What is the coefficient of

in the power series expansion of

?

I'm having trouble expanding this. Could someone explain how to solve it? Cheers.

**Jhevon** · January 26th 2009, 10:06 AM

Originally Posted by Haris

What is the coefficient of

in the power series expansion of

?

I'm having trouble expanding this. Could someone explain how to solve it? Cheers.

you don't need to expand anything

let $f(x) = \frac 1{(9 + 5x)^{1/4}}$

the coefficient of the $x^2$ -term is given by

$\frac {f''(0)}{2!}$

**Opalg** · January 26th 2009, 10:08 AM

Originally Posted by Haris

What is the coefficient of

in the power series expansion of

?

I'm having trouble expanding this. Could someone explain how to solve it?

Write it as $9^{-1/4}\bigl(1+\tfrac{5x}9\bigr)^{-1/4}$ . Then use the binomial expansion of $(1+t)^{-1/4}$ , taking t=5x/9.

Edit. Alternatively, use Jhevon's method. It's equally good.

Thread: Series Expansion

LinkBack

Thread Tools

Display

Series Expansion

Similar Math Help Forum Discussions

series expansion for sin(e^x)

Series expansion?

Help with Series Expansion

series expansion

Series Expansion/Taylor Series Help

Search Tags