Posted by Joel on October 16, 2002 at 18:25:23:
In Reply to: Re: Have you done "derivatives [df(x)/dx]" yet ? (n/t) posted by Ronnie Dobbs on October 16, 2002 at 16:57:13:
: No, we are not quite there yet...I believe we study that in the next unit.
:
: : : Find the slope of the tangent line to the curve y = x^3 at the point (-1, -1).
: : : So we're using...
: : : lim x-> -1
: : : [ f(x) - f(a) ] / x - a
: : : lim x-> -1
: : : [x^3 - f(-1)] / x - (-1) = [x^3 - (-1)] / x - (-1)
: : : = lim x->-1 [x^3 + 1] / x + 1
: : : This is where I'm stuck...can anyone shed some light on what my next step(s) is? Thanks.
: : :
you can factor that numerator into (x+1)*(x^2-x+1) and I'm sure you will see what to do next.