Hey guys,
Wondering if anyone could help me with this question:
The equation x^3 + 3px^2 + 3qx + r = 0, where p^2 cannot = q has a double root. Show that (pq-r)^2 = 4(p^2-q)(q^2-pr).
I've tried finding P'(x) and letting it = 0, but i don't know where to go from there.
Thanks guys, in advance.