# Math Help - parameterization

1. ## parameterization

a parameterization for a surface called a helicoid is given: f(s,t)= (scost,ssint,t)

compute the surface area of the helicoid corresponding to (s,t): [0,1]x[0,2pi]

sorry i'm completely lost on this problem..any ideas how to set it up?

2. Originally Posted by calc626
a parameterization for a surface called a helicoid is given: f(s,t)= (scost,ssint,t)

compute the surface area of the helicoid corresponding to (s,t): [0,1]x[0,2pi]

sorry i'm completely lost on this problem..any ideas how to set it up?
Usually we have the surface given parametrically as

$
{\bf r} = {\bf r}(u,v)
$

and the surface area is given by

$\iint_R || {\bf r_u \times r_v } || dA\,\, (1)$

Here, we have

$
{\bf f} = < s \cos t,s \sin t,t>
$

so identify ${\bf r = f},\;\;u = s$ and $v = t$ and follow (1)