Question

pt. on graph of f(x)=x^2-1 closest to (-4,0)?
i'm getting (-√3/2,1/2) but not sure

Answer 1

That doesn't satisfy the f(x) so it can't be.

Answer 2

Unless you mean sqrt(3/2) that is.

Answer 3

yes there should be a sqrt symbol there? not visible?

Answer 4

hey simon i need ur help

Answer 5

with what?

Answer 6

you missed brackets to make it what you wanted. I think you answer is wrong as it doesn't satisfy the optimisation equation.

Answer 7

after ur done with this problem. could u help me with the problem that u answered for me. i whata kno how u got the answer step by step :) pretty plez

Answer 8

i was minimizing 4x^3-2x+8

Answer 9

flyqueen, maybe it was another simon?

Answer 10

You shouldn't be minimising that, you should be finding the when it equals 0.

Answer 11

oh lol ur rite ur the wrong simon sorry

Answer 12

thats what i meant, and got x=-sqrt(3/2), y=1/2?

Answer 13

Okay, now put -sqrt(3/2) into that equation. It doesn't equal 0.

Answer 14

Answer is x = -1.3917... whatever that is in a nice form if there is one.

Answer 15

how did you solve for zero?
im getting 4x^3-2x+8=0
4x^3-2x=-8
2x(x^2-1)=-8
x=-4 or x=+-sqrt(-7)

Answer 16

I put it into a calculator. If you cant spot a factorisation, cubics are typically hard to solve by hand. Use a calculator or the standard formula.

I don't understand how you got to your answer given the line above it, but none of those x solve the equation.

Answer 17

thanks