# Hi, I'm in AP Calculus and I feel really stupid

Hi, I'm in AP Calculus and I feel really stupid :(

I feel really stupid because it's only the first week of school and I'm struggling with the review (I forgot a lot over the summer)

I'm posed with these two problems (in addition to many other but I don't want to bore you all :

(a)Solve for x: x^2 = 2^x
(b)Solve for X: x^2 > 2^x

My first plan of attack for (a) was to do this:

2logx = xlog2

Thanks,

Daniel

Related Introductory Physics Homework Help News on Phys.org
Also, does anyone know any forums similar to these (not physics though) which can help you with math homework? I posted here because I'm sure a lot of you are in high levels of math too.

jcsd
Gold Member

Hurkyl
Staff Emeritus
Gold Member
The only real way to do (a) is by inspection. Make a few guesses as to the answer, you'll probably hit upon the two solutions.

As for (b), are you reviewing calculus or previous courses? Are you allowed to solve problems like this by looking at the graph in a calculator?

I tried graphing too, and that gave me 3 different intersections when I set y=x^2 and y=2^x. I still wouldn't know how to do (b) with graphing, and I'm sure there's a way to do (a) without graphing.

jcsd
Gold Member
Originally posted by Daniel
I tried graphing too, and that gave me 3 different intersections when I set y=x^2 and y=2^x. I still wouldn't know how to do (b) with graphing, and I'm sure there's a way to do (a) without graphing.
There is only one intersection for those two lines.

I found an intersection at 2, -.7666, and one at 4. I used ti83+ and I'm in degree mode.

As for (b), are you reviewing calculus or previous courses? Are you allowed to solve problems like this by looking at the graph in a calculator?
We are reviewing previous courses. I'm allowed to use a calculator, but I forgot how to with a >.

jcsd
Gold Member
Originally posted by Daniel
I found an intersection at 2, -.7666, and one at 4. I used ti83+ and I'm in degree mode.
oops sorry I've mad a mistake.

jcsd
Gold Member
just to correct my first post, this is were I made the mistake, i should of gotten:

x1/x = 21/2

jcsd
Gold Member
The only way your going to solve this I think is by using your graphing calculator.

jcsd
Gold Member
b) should be 2 < x < 4 and x < -0.7666

jcsd
Gold Member
basically again just looking at the graph.

HallsofIvy