Posted by **Jacob** on Wednesday, February 20, 2013 at 4:52pm.

Find the first and second derivative of the function:

x/(7x+10)

Using quotient rule. This is part of my homework in the section named "Higher Order Derivatives". I am confused on getting the second derivative, as I found the first derivative to be 10/(7x+10)^2

- Applied Calculus -
**JJ**, Wednesday, February 20, 2013 at 4:59pm
I agree with your first derivative.

Now, start with 10/(7x+10)^2 and take the derivative again.

Denom times deriv of numerator = 0

since deriv of 10 = 0

minus the numer time the deriv of the denomin.

- 10(2(7x+10)7) this is the chain rule

You need to simplify this expression

all over the denominator squared which makes the denominator to the 4th power.

- Applied Calculus -
**bobpursley**, Wednesday, February 20, 2013 at 5:01pm
y=x/(7x+10)

y'=1/( ) - 7x/( )^2

= (7x+10)x - 7x)/ (7x+10)^2

and that is not equal to your answer.

= (7x^2 +3x)/(7x+10)^2

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