Question

Show that f(x) = 2x^3 + x^2 + 2 has at least one real zero. Find an interval of length 1/
4 that contains a
zero of f.
Please help

Answer 1

You know descartes rule of signs?

Answer 2

@Supenova ?

Answer 3

Basically u can use intermidiate value theorem

Answer 4

f(x) = 2x3 + x2 + 2 has at least one real zero. Find an interval of length 1/4 that contains a zero of f(x).

Answer 5

@ yrelhan4, no i don't

Answer 6

will find out tho

Answer 7

The part about at least one real zero is easy: it's a poly with only real coefficients, and an odd order. Complex roots must come in pairs to satisfy the only real coefficients part, and there is an odd number of roots (3) -> must be 1 or 3 real roots.