[SOLVED] Help with domain

**el123** · October 22nd 2009, 05:50 PM

$f(x)=e^{-x^2}$

Find domain.
Find first and second derivative

Can some one please take me through this?

**skeeter** · October 22nd 2009, 06:09 PM

Originally Posted by el123

$f(x)=e^{-x^2}$

Find domain.
Find first and second derivative

Can some one please take me through this?

domain is all real numbers

$f'(x) = e^{-x^2} \cdot (-2x)$

$f''(x) = e^{-x^2} \cdot (-2) + (-2x) \cdot e^{-x^2} \cdot (-2x)$

you can clean up the algebra

**pickslides** · October 22nd 2009, 06:14 PM

Originally Posted by el123

$f(x)=e^{-x^2}$

Find domain.

The function is defined for all values of x as you can square any real number and raise any real number over e.

Originally Posted by el123

$f(x)=e^{-x^2}$

Find first and second derivative

Consider

If $y = e^{f(x)} \Rightarrow \frac{dy}{dx} = f'(x)e^{f(x)}$

to find the 1st.

Repeat this in conjunction with the product rule on the 1st to obtain the second.

**ux0** · October 22nd 2009, 06:58 PM

Originally Posted by el123

$f(x)=e^{-x^2}$

Find domain.
Find first and second derivative

Can some one please take me through this?

The easiest way to understand domain is to ask yourself what values of X can i put into the function f(x)?

The derivative is just

$e^udu$

where your

$u=-X^2$

$<br /> f'(x)= -2xe^{-X^2}$

and ill leave you to find the second one, in which case you will have to use the chain rule...

$f(x)g(x)=f'(x)g(x)+f(x)g'(x)$

Thread: [SOLVED] Help with domain

LinkBack

Thread Tools

Display

[SOLVED] Help with domain

Similar Math Help Forum Discussions

[SOLVED] domain and range

[SOLVED] Find the Domain: f(x) = 2e^(2 - x) + 1

[SOLVED] Domain

[SOLVED] Domain and range

[SOLVED] Domain

Search Tags