How Do You Compute Arc Length and Surface Area for the Exponential Curve e^x?

froogle30
Messages
1
Reaction score
0
C: y=f(x)=e^x, where x is all real numbers.
Compute the arc-length function S for C relative to C's y-intercept
Computer the area S for the surface generated by revolving the curve C*:y=f(x)=e&x, where x is [0,a] and a is a positive constant, about the x-axis

I've been trying this problem for 2 weeks and have gotten stuck. I usually don't ask for help because I figure that help doesn't get me anywhere and that I prefer to do everything on my own, but this problem is due after spring break, which is on Monday. I've done this problem to the point where my head literally feels like exploding. Please..someone help.

The answer I ended up with ln |csc theta - cotangent theta|. Thanks
 
Last edited:
Physics news on Phys.org
Welcome to PF!

Hi froogle30! Welcome to PF! :smile:

(have a theta: θ and a pi: π and try using the X2 tag just above the Reply box :wink:)
froogle30 said:
C: y=f(x)=e^x, where x is all real numbers.
Compute the arc-length function S for C relative to C's y-intercept
Computer the area S for the surface generated by revolving the curve C*:y=f(x)=e&x, where x is [0,a] and a is a positive constant, about the x-axis

The answer I ended up with ln |csc theta - cotangent theta|.

Show us how you got ln(cscθ - cotθ), and then we can see what went wrong, and we'll know how to help :smile:
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top