Question

Root of equation help *question attached below* Will give medal

Answer 1

So I've already completed part a of this question and I used the Intermediate Value Theorem to show that this root exists, but I'm having some difficulty with part b. Should I draw a graph? Or discriminant?

Answer 2

HI!!

Answer 3

here is my guess
take the derivative, and assert that on that interval the function is either strictly increasing or decreasing
that is just a guess, i didn't do it

Answer 4

yeah that works!!

Answer 5

@iTiaax you got this?

Answer 6

Are we talking about stationery points?

Answer 7

hmmm no

Answer 8

if the derivative is positive over that interval, that means that on that interval the function is going up (increasing as the math teachers say)

Answer 9

if it is is strictly increasing then it cannot be zero twice

Answer 10

so for point b. i think you need to know in function of discriminant when a function will have just one root

ok ?

Answer 11

because there are 3 cases

when D. the discriminant is greater than zero so this result 2 different roots so when the D. discriminant is equal with zero what will result ? do you know it ?

Answer 12

so this is what you need to know and using for point b.

ok ?

Answer 13

can you calcul it now ?

Answer 14

can you calcul the discriminant ?

Answer 15

so there are x^2 +kx -1 =0

yes ?

Answer 16

so you dont like cooperate nothing than i not can help you sorry