Expert: Bobby Soltani - 9/25/2004

Question
find a value for the constant k so that

f(x)=the set of (sin3x)/x, x does not = 0
                k, x=0

Answer
Hi Joanne,

There are a couple of ways to solve this one.  If you are in algebra, the easiest way is to graph it on a calculator or graph paper.  You will see that k=3 when x=0.

If you are in a calculus class, you can use l'hopital's rule to solve it.  To do this, you take the derivative of the top and bottom, and plug in x = 0 in that equation.  Here's how

f = (sin 3x)/(x)
take derivative of top and bottom
=(3*cos x)/1
plug in x = 0
= 3

Either way you get k = 3.

Bobby