Check out some similar questions!

leebaseball50 · Aug 11, 2007, 02:29 PM

g(x)=x^2+3x-1
find (g(x+(delta symbol)x) - g(x)) / ((delta sym)x)

how do I solve this? Please help me!

does the delta symbol mean change in this case? I don't no what to do :(:confused: :mad:

galactus · Aug 11, 2007, 04:25 PM

Yes, delta means the 'change in x'. This is the definition of a derivative.

There should be a graph in your calculus book which will help show you what this means.

Except, most times, h is used instead if delta(x). I will use h.

It's based on the slope of a line. The instantaneous rate of change of y with respect to x at

a point x_0 is:

$slope=m=\lim_{x_{1}\to\(x_{0})}\frac{f(x_{1})-f(x_{0})}{x_{1}-<br /> <br /> x_{0}}$

$x_{1}-x_{0}=h$ . Then, $x_{1}=x_{0}+h$ and h approaches 0

as $x_{1}$ approaches $x_{0}$ . Then we can write the slope of

the line as $m=\lim_{h\to\0}\frac{f(x_{0}+h)-f(x_{0})}{h}$

I will show you how this works and you try another. OK?

$\lim_{h\to\0}\frac{f(x+h)-f(x)}{h}$

Wherever you have an x, insert x+h. $f(x+h)=(x+h)^{2}+3(x+h)-1$

You have $\lim_{h\to\0}\frac{[(x+h)^{2}+3(x+h)-1]-[x^{2}+3x-1]}{h}$

Which simplifies to(you can do the algebra):

$\lim_{h\to\0}\frac{2xh+h^{2}+3h}{h}$

Now, what do you have as h approaches 0? The derivative of $x^{2}+2x-1$

Toms777 · Aug 11, 2007, 04:26 PM

Originally Posted by leebaseball50

g(x)=x^2+3x-1
find (g(x+(delta symbol)x) - g(x)) / ((delta sym)x)

how do i solve this? please help me!

does the delta symbol mean change in this case? i don't no what to do :(:confused: :mad:

Delta is a Greek letter that looks like a triangle on its base. This is one: Δ

Tom