I need some more help. Find a gneral expression for the slope of a tangent line for the given curve, then find the slopes for the given values of x.
$\displaystyle y=x^2$ ; $\displaystyle x=2$ , $\displaystyle x=-1$
the general form for the slope of a line tangent to $\displaystyle f(x)$ is $\displaystyle f'(x)$...so for $\displaystyle f(x)=x^2$ the slope at any point is $\displaystyle f'(x)=2x$...now to get the two slopes evaluate them in the derivatives $\displaystyle f'(2)=2\cdot{2}=4$ and $\displaystyle f'(-1)=2\cdot{-1}=-2$