2. Let C be the curve in R3 defined by the parametric equations

x(t) = cos(et)

y(t) = sin(et)

z(t) = et

for t in [0,2]. What is the length of C?

 

A.

B.

C.

D.

E.

 

Solution: The answer is A

 

The length of a curve C in R3 is the integral of the square root of the sum of the squares of the derivatives of each parametric curve over the interval [a,b]. Thus, the derivatives of the above parametric equations are,

So that the length of curve C, denoted L, is