The cubic polynomial P(x) =x3 +rx2 +sx +t
, where r, s and t are real numbers, has three real zeros, 1, αand –α.
(i) Find the value of r.
(ii) Find the value of s +t.
P(x) =x3 +rx2 +sx +t.
The cubic polynomial P(x) =x3 +rx2 +sx +t
, where r, s and t are real numbers, has three real zeros, 1, αand –α.
(i) Find the value of r.
(ii) Find the value of s +t.
P(x) =x3 +rx2 +sx +t.
with working out please.
This is not as hard as it may look.
Write , expand, and then match the coefficients.
Note that (in other words, you can skip the step of writing out that expansion explicitly by noticing there is a difference of squares).
Almost. r = -1, not 1. I hope you see how I matched the coefficients, because that's the main point of the problem, and you might get more problems like it.
Almost. r = -1, not 1. I hope you see how I matched the coefficients, because that's the main point of the problem, and you might get more problems like it.