I need help differentiating this:

y = [ 7+xf(x) ] / sqrt(x)

Thanks!

Printable View

- Oct 10th 2010, 03:50 PMmobliciousQuotient / Product Rule help
I need help differentiating this:

y = [ 7+xf(x) ] / sqrt(x)

Thanks! - Oct 10th 2010, 03:55 PMJhevon
How did you begin? where are you stuck? you know what the quotient and product rules say, right?

$\displaystyle \dsiplaystyle y' = \frac {\sqrt x \cdot \frac d{dx}(7 + xf(x)) - (7 + xf(x)) \cdot \frac d{dx} \sqrt x}{(\sqrt x)^2}$

That's plugging it into the quotient rule. now what? - Oct 10th 2010, 04:06 PMmoblicious
- Oct 10th 2010, 04:09 PMJhevon
- Oct 10th 2010, 04:43 PMmoblicious
f(x)+xf'(x)sqrt(x)-(7+f(x)+xf'(x))-1/2x^(-1/2) / x?

- Oct 10th 2010, 04:57 PMJhevon
- Oct 10th 2010, 06:33 PMmoblicious
I used every parentheses correctly, don't know what you were looking at.

Is it (xf(x)+2x^2f'(x)-7) / 2x^(3/2) ? - Oct 10th 2010, 06:38 PMJhevon
I can say with certainty that you didn't. for one, the numerator and denominator should be encapsulated in parentheses when typing like that. if you look at what you typed, this was not the case; the "f(x)+xf'(x)" should have been in parentheses also... anyway

Quote:

Is it (xf(x)+2x^2f'(x)-7) / 2x^(3/2) ?

- Oct 10th 2010, 06:52 PMmoblicious
My apologies then. Thanks for the help.

- Oct 10th 2010, 06:53 PMJhevon