Question

i need help maximum and minimum of the function @satellite73

Answer 1

@acxbox22

Answer 2

find the vertex
the y value of vertex is the minimum in this case

Answer 3

i got B

Answer 4

@timo86m

Answer 5

@Spectrum

Answer 6

hi

Answer 7

first coordinate of the vertex is \(-\frac{b}{2a}\) which in your case is \(-\frac{28}{4}=-7\)
second coordinate of the vertex is what you get when you replace \(x\) by \(-7\)

Answer 8

y = 2 x^2 + 28x -8
dy/dx = 0 = 4x +28
extreme value at x=-7
(d/dx)(dy/dx) = 4 >0
so that extreme value is a minimum

Answer 9

\[f(-7)=2\times (-7)^2+28\times (-7)-8=-106\] and that is your minimum value

Answer 10

as usual, the answer is C,
it is always C

Answer 11

the question is rather ill posed because the function has an "absolute" minimum, it is \(-106\) and it has no relative maximum

Answer 12

@douglaswinslowcooper i seriously doubt this is a calculus question, although i guess i could be wrong
in any case, no calc necessary for this one

Answer 13

You are probably right on the first count and certainly the second. Stil, some may profit from the calculus approach.

Answer 14

thanks everyone!