Wierd integral problem

**Latszer** · November 24th 2009, 02:31 PM

Let the following be true. (all the stuff at the bottom.)

Find the value of the following integral.

$\int_a^b [m*g(x)+(n*f(x))^2]$

That is all the problem tells me, thanks for any help.

**Soroban** · November 24th 2009, 03:01 PM

Hello, Latszer!

I'm guessing at what the problem said . . .

Given:
. . $\int^b_a f(x)\,dx \;=\;8$

. . $\int^b_a\bigg[f(x)\bigg]^2dx \;=\;13$

. . $\int^b_a g(x)\,dx \;=\;1$

. . $\int^b_a\bigg[g(x)\bigg]^2dx \;=\;2$

Find the value of: . $\int_a^b \bigg(m\cdot g(x) + \left[n\cdot f(x)\right]^2\bigg)\,dx$

Exactly where is your difficulty?

$\int^b_a \bigg( m\cdot g(x) + [n\cdot f(x)]^2\bigg)\,dx \quad=\quad \int^b_a\bigg(m\cdot g(x) + n^2\cdot [f(x)]^2 \bigg)\,dx$

. . . $= \quad m\underbrace{\int^b_a\!\! g(x)\,dx}_{\text{This is 1}} \;+\; n^2\underbrace{\int^b_a[f(x)]^2dx}_{\text{This is 13}} \quad=\quad m + 13n^2$

**Latszer** · November 24th 2009, 03:10 PM

the problem says g(t) for the last two, I wrote it right.

**Jameson** · November 24th 2009, 03:12 PM

Originally Posted by Latszer

the problem says g(t) for the last two, I wrote it right.

Then there must be some way to express g(x) that isn't given in your post. Otherwise Soroban gave the right answer. If you didn't make a typo the problem doesn't make sense, do you see why?

Thread: Wierd integral problem

LinkBack

Thread Tools

Display

Wierd integral problem

Similar Math Help Forum Discussions

Wierd product contour integral

Wierd reationship in spheres

Wierd differential equation

wierd derivative question

Wierd Algebra Problem

Search Tags