Question

differentiate y=x/square root (x^2+1)

Answer 1

Use the quotient rule. Do you know what that is?

Answer 2

yes i just wanted to know the answer because i keep getting something different to the answer given

Answer 3

so i'm not sure where i went wrong

Answer 4

What did you get?

Answer 5

1/(x^2+1)

Answer 6

I think you forgot -x

Answer 7

and the correct answer according to the solution is 1/(x^2+1)^(3/2)

Answer 8

I got
\[(1/(x^2+1) )-x\]

Answer 9

The derivative is:
\[-\frac{x^2}{\left(1+x^2\right)^{3/2}}+\frac{1}{\sqrt{1+x^2}}=\frac{1}{\left(1+x^2\right)^{3/2}} \]

Answer 10

robtobey could you show me your working out before reaching what you had come up with in the above post thanks!

Answer 11

Used Mathematica 8. The request for the derivative from that program was:\[D\left[\frac{x}{\sqrt{1+x^2}},x\right] \]
Browse over to WolframAlpha.com and enter:
derivative of x/square root (x^2+1)
Seclect show steps
See the attachment

Answer 12

Product rule:

\[ \dfrac{\mathbb{d}}{\mathbb{d}x}(u\cdot v)=u\cdot \dfrac{\mathbb{d}v}{\mathbb{d}x}+v\cdot \dfrac{\mathbb{d}u}{\mathbb{d}x} \]

where u, v are functions of x.


The quotient rule is just extra baggage.

Answer 13

thank you robtobey,romero and INewton!! ^.^

Answer 14

¬_¬ It was all robtobey.

Answer 15

but INewton made a lovely conclusion to the question!

Answer 16

=]