Question

find the minimum value of the function f(x)= x^2+9x-16

a. -36.250
b. -2.500
c. there is no minimum
d. cannot be determined

to three decimal places , find the value of the first positive x-interept for the function f(x)= 2cos(x+4)

a. 1.712 ( not right choice)
b. 0.12
c. -2.429
d. -2.712

Answer 1

A( -36.250)

Answer 2

Sorry. I only know how to do the first one

Answer 3

okay ty so much!

Answer 4

@sleepyhead314 I got a. -36.250 for the first one

Answer 5

that is right! :)

Answer 6

what about the second one

Answer 7

do you think you can help me with this one?
a box is to be constructed from a sheet of cardboard that is 10 cm by 50 cm by cutting out squares of length x by x from each corner and bending up the sides. what is the maximum volume the box could have?

Answer 8

@magy33 would you like an explanation on how to get that?

Answer 9

pz explain I have been trying to understand all day xd

Answer 10

minimum value is a critical point of the function f(x)

critical points of the function are at when f'(x) = 0
(when the derivative of f(x) equals 0)

find the derivative of f(x) = f'(x) = ?

Answer 11

f'(x) = 2x + 9
(power rule...)
then 2x + 9 = 0 solve for x

then when you get that
plug x back in to f(x) = x^2 +9x - 16

Answer 12

I've gtg now sorry :(

Answer 13

o ty

Answer 14

@nikvist
@Hero
@robtobey
@FibonacciChick666 can you help me answer question 2 and three in here plz I only have couple minutes left. I will fan and medal

Answer 15

there is no .. minimum