Ask your own question, for FREE!
Mathematics 16 Online
OpenStudy (lukecrayonz):

Difference quotient :) http://gyazo.com/892a400eceec44ef8f05e3ae87e1cdde

OpenStudy (lukecrayonz):

So I start out with -2(x+h)^2-(x+h)-2

OpenStudy (lukecrayonz):

Expand, simplify, and I get (-h-2 h^2-4 h x-4 x^2)/h

OpenStudy (lukecrayonz):

Luigi I know you know this

OpenStudy (luigi0210):

I would help, but Siths is about to give a lecture

OpenStudy (lukecrayonz):

Good :D I need it haha

OpenStudy (anonymous):

-2h^2-h-4hx-4x^2/h

OpenStudy (anonymous):

simplified

OpenStudy (anonymous):

\[f(x)=-2x^2-x-2~~\Rightarrow~~\begin{align*}f(x+h)&=-2(x+h)^2-(x+h)-2\\ &=-2(x^2+2xh+h^2)-x-h-2\\ &=-2x^2-2xh-2h^2-x-h-2 \end{align*}\] So the difference quotient becomes \[\begin{align*}\frac{f(x+h)-f(x)}{h}&=\frac{\left(-2x^2-2xh-2h^2-x-h-2\right)-\left(-2x^2-x-2\right)}{h}\\ &=\frac{-2xh-2h^2-h}{h} \end{align*}\]

OpenStudy (luigi0210):

^Told ya

OpenStudy (anonymous):

:)

OpenStudy (lukecrayonz):

So then -2x-2h is my final answer?

OpenStudy (lukecrayonz):

Sith you can't leave btw, I'm borrowing you for about 30 minutes :D http://gyazo.com/e1df2303d768e488acc74aced45b31c7

OpenStudy (luigi0210):

Poor Siths :P

OpenStudy (lukecrayonz):

1992=5.5 1999=3.5

OpenStudy (lukecrayonz):

it's -0.286 right?

OpenStudy (anonymous):

Should be \(-2x-2h-1\).

OpenStudy (lukecrayonz):

Oh right, dividing variables is to 1. Stupid me :O

OpenStudy (anonymous):

For the graph problem, you have to use a variation of the difference quotient. Average rate of change of a function \(f\) over some interval \([a,b]\) is given by \[\frac{f(b)-f(a)}{b-a}\]

OpenStudy (anonymous):

So for part A, \(a=1992\) and \(b=1999\), and it looks like \(f(a)=5.5\) and \(f(b)=3.5\). For B, \(a=2004\) and \(b=2007\), and \(f(a)=1.5\) and \(f(b)=1\). Plug in the values.

OpenStudy (lukecrayonz):

-3.5 for 1992-1999 6 for 2004-2007?

OpenStudy (lukecrayonz):

-6 sorry

OpenStudy (anonymous):

\[\frac{3.5-5.5}{1999-1992}=\frac{-2}{7}\] \[\frac{1-1.5}{2007-2004}=\frac{-0.5}{3}=-6\]

OpenStudy (lukecrayonz):

Oh okay I had it right haha

OpenStudy (lukecrayonz):

BRB:-)

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!