drawing graph of quartic polynominal and rewriting

K

kais

New member
Joined
Jul 20, 2015
Messages
16
Hey guys im having slight trouble with a math question, i was wondering if someone could point me to a video or help answer a similar question so i can see how its done

Let f be a quartic polynomial (ie. a polynomial of degree 4). Suppose that f has zeros at −2, 1, 3, 4 and that f(0) = 4

.• Sketch a graph of f .

• If f(x) is written in the form f(x) = A(x− a)(x− b)(x− c)(x− d) ,then find the values of A, a, b, c, d.

Cheers in advanced
 
Hey guys im having a bit of trouble with a math question and i was wondering if someone could link me to a video or do a similar sum so i can get the idea on how to do it
Let f be a quartic polynomial (ie. a polynomial of degree 4). Suppose that f has zeros at −2, 1, 3, 4 and that f(0) = 4.
• Sketch a graph of f .
• If f(x) is written in the form f(x) = A(x− a)(x− b)(x− c)(x− d)

would i be right in saying that f(x) = 4(x+2)(x-1)(x-3)(x-4) ? and how do i work out the polynomial from zeroes?

Cheers in advance!
 
kais said:
Hey guys im having a bit of trouble with a math question and i was wondering if someone could link me to a video or do a similar sum so i can get the idea on how to do it
Let f be a quartic polynomial (ie. a polynomial of degree 4). Suppose that f has zeros at −2, 1, 3, 4 and that f(0) = 4.
• Sketch a graph of f .
• If f(x) is written in the form f(x) = A(x− a)(x− b)(x− c)(x− d)

would i be right in saying that f(x) = 4(x+2)(x-1)(x-3)(x-4) ? and how do i work out the polynomial from zeroes?

Cheers in advance!
Click to expand...

Almost....

f(x) = A(x+2)(x-1)(x-3)(x-4) → f(0) = A * 2 * (-1) * (-3) *(-4) → 4 = A * (-24) → A = ?
 
i understand how you get to A * (-24) , but how can any number multiplied by -24 equal to 4? sorry im not quite getting it, but thank you so much for your help so far
 
kais said:
i understand how you get to A * (-24) , but how can any number multiplied by -24 equal to 4? sorry im not quite getting it, but thank you so much for your help so far
Click to expand...
Can you divide -24 buy a number and get 4? Then instead of dividing -24 by that number you can multiply -24 by the recriprocal of that number. You can always change division problems into multiplication problems!
 
ahhh thanks a lot for your help guys! made the rest of the questions so much easier!!!
 
You must log in or register to reply here.
Top