## anonymous 5 years ago Last one for the night and my homework is done. Woohoo. :) When P dollars is invested at interest rate i, compounded annually, for t years, the investment grows to A dollars, where A=P(1 + i)^t. Find the interest rate if $2490 grows to$3630 in 2 years. Round your answer to the nearest hundredth of a percent.

1. anonymous

3630/2490 = x^2 +2x+1

2. anonymous

go from there

3. anonymous

$2490(1+i)^2=3630$ $(1+i)^2=\frac{3630}{2490}=1.4578$

4. anonymous

$1+i=\sqrt{1.4578}$ $i=\sqrt{1.4578}-1$

5. anonymous

$i=.2074$ or 20.74% i would love to get that!

6. anonymous

hope this helped you get through the assignment.

7. anonymous

you are really good. thanks man.

8. anonymous

welcome. oh one more thing. if you are going to solve $(x+1)^2=somthing$ don't multiply out. just take $x+1=\pm\sqrt{something}$

9. anonymous

we didn't need the minus here because we wanted a positive answer

10. anonymous

ok. will remember. my head hurts. haha. thanks

11. anonymous

welcome