# Thread: C3 differentiation

1. ## C3 differentiation

http://img508.imageshack.us/my.php?image=graphah5.png

The diagram shows the curve with the equation y = (x+3)(x-1)^3 which crosses the x-axis at P and Q and has a minimum point at R

a) write down the coordinates of P and Q
b) find the coordinates of R

i am really stuck here but have a feeling its easier than i think. any help would be great

2. Originally Posted by andyp999
ImageShack - Hosting :: graphah5.png

The diagram shows the curve with the equation y = (x+3)(x-1)^3 which crosses the x-axis at P and Q and has a minimum point at R

a) write down the coordinates of P and Q
b) find the coordinates of R

i am really stuck here but have a feeling its easier than i think. any help would be great
Just apply what you know. X-intercepts implies that those values of x make the function zero. So $\displaystyle (x+3)(x-1)^3=0\implies{x+3=0\text{ or }(x-1)^3=0}$. And to find the minimum point you can attempt to locate the vertex or you can differentiate and use the second derivative test.