SOLUTION: Given f(x) = 3x + 5x^2 − 2 − x^3 do each of the following: A) Write it in standard form. B) State its degree C) Identify the type (even/odd) D) What is the leading coeffi

Algebra ->  Testmodule -> SOLUTION: Given f(x) = 3x + 5x^2 − 2 − x^3 do each of the following: A) Write it in standard form. B) State its degree C) Identify the type (even/odd) D) What is the leading coeffi      Log On


   



Question 1154824: Given f(x) = 3x + 5x^2 − 2 − x^3 do each of the following:
A) Write it in standard form.
B) State its degree
C) Identify the type (even/odd)
D) What is the leading coefficient?
E) How many roots are there?
F) Describe the end behaviors x→ -∞, f(x)→_______ and as x→∞, f(x)→ _______

Found 2 solutions by greenestamps, MathLover1:
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


A) Rewrite the polynomial in standard form -- i.e., in descending powers of the variable.

-x%5E3%2B5x%5E2%2B3x-2

B) The degree of the polynomial is the degree of the leading term: 3

C) The polynomial has terms of both even and odd degrees; the polynomial as a whole is neither even nor odd.

D) The leading coefficient is the coefficient of the leading term: -1

E) The number of roots is the degree of the polynomial: 3

F) The end behavior is determined by the degree of the polynomial and the sign of the leading coefficient. Odd degree and negative leading coefficient means the value goes to +infinity as x goes to -infinity, and to -infinity as x goes to +infinity.

A graph which shows the end behavior clearly....

graph%28400%2C400%2C-5%2C6%2C-100%2C100%2C3x%2B5x%5E2-2-x%5E3%29


Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

Given f%28x%29+=+3x+%2B+5x%5E2+-2+-x%5E3 do each of the following:

A) Write it in standard form.
A cubic function has the standard form of f%28x%29+=+ax%5E3+%2B+bx%5E2+%2B+cx+%2B+d
f%28x%29+=-x%5E3%2B+5x%5E2%2B+3x++-2+
B) State its degree
degree 3
C) Identify the type (even/odd)
I'll plug -x in for x, and simplify to check if this function is even:
f%28x%29+=-%28-x%29%5E3%2B+5%28-x%29%5E2%2B+3%28-x%29++-2+
f%28x%29+=x%5E3+%2B+5+x%5E2+-+3+x+-+2+
I can see, by a quick comparison, that this does not match what I'd started with, so this function is not even.
What about odd?
-f%28x%29+=-%28-x%5E3%29-%28%2B+5x%5E2%29-%28%2B+3x%29-%28++-2+%29
-f%28x%29+=x%5E3-+5x%5E2-3x%2B2+
This doesn't match what I came up with, either. So the original function isn't odd, either.
=> f+%28x%29 is neither even nor odd
D) What is the leading coefficient?
the leading coefficient is -1

E) How many roots are there?
there are 3 roots
F) Describe the end behaviors
Cubic functions are functions with a degree of 3 (hence cubic ), which is odd. Linear functions and functions with odd degrees have opposite end behaviors.
x-%3E+-infinity, f%28x%29-%3Einfinity and as x-%3Einfinity, f%28x%29-%3E+-infinity