interval and symmetry questions

xingz

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Dec 2, 2006
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6
I would appreciate if someone can solve these problems for me, seeing there's some exceptional smart people here. It's a review sheet but our teacher didn't take it up...

Thanks a lot~!

calc.png
 
For #5:

\(\displaystyle \L\\g(x)=2x^{3}+mx^{2}+nx+7\)

We know that (2,5) is on the graph.

\(\displaystyle \L\\2(2)^{3}+m(2)^{2}+2n+7=5\Rightarrow{4m+2n=-18}\)


We need another equation in order to solve for m and n.

Dividing g(x) by x+3, we get:

\(\displaystyle \L\\2x^{2}+mx-6x-3m+n+18+\frac{9m-3n-47}{x+3}\)

The remainder is \(\displaystyle 9m-3n-47=-95\)

Now, you have 2 equation with 2 unknowns:

\(\displaystyle \L\\9m-3n=-48\)
\(\displaystyle \L\\4m+2n=-18\)

Solve for m and n.
 
Thanks for the answer for question 5!

Can anyone help me out with question 3 and question 4 part b? thanks
 
For #3. Graph the function. Check to see if it's even or odd.

If even, then f(-x)=f(x). That is, if you put -x in place of x in the function, you get the same thing as the original.

If it's odd, then f(-x)=-f(x). That is, if you put -x in your function you get back the negative of it.

For #4b. Play around with some values and see where it's greater than 0 and where it's less than 0.
 
xingz said:
Can anyone help me out with question 3 and question 4 part b? thanks
For 4b you have the x-intercepts, which divide the domain into regions where f(x) is >0 or <0, so all that is left to do is test the sign of f(x) at values of x between the x-intercepts.
 
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