SOLUTION: For the polynomial Function : F(x)=-2(x + 1/2) (x+4)^3 a)List each real zero and its multiplicity: b)Determine whether graph crosses or touches the x-axis at each x-intercept: c

Algebra ->  Rational-functions -> SOLUTION: For the polynomial Function : F(x)=-2(x + 1/2) (x+4)^3 a)List each real zero and its multiplicity: b)Determine whether graph crosses or touches the x-axis at each x-intercept: c      Log On


   



Question 1189459: For the polynomial Function : F(x)=-2(x + 1/2) (x+4)^3
a)List each real zero and its multiplicity:
b)Determine whether graph crosses or touches the x-axis at each x-intercept:
c)Determine the behavior of the graph near each x-intercept(zero):
d)Determine the maximum number of turning point on the graph:
e)Determine the end behavior, that is finding the power function that the graph of
f resembles for large values of |x|:

Found 2 solutions by MathLover1, Boreal:
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

For the polynomial Function :
f%28x%29=-2%28x+%2B+1%2F2%29+%28x%2B4%29%5E3

a)List each real zero and its multiplicity:
-2%28x+%2B+1%2F2%29+%28x%2B4%29%5E3=0
if %28x+%2B+1%2F2%29=0=>x=-1%2F2,..... multiplicity 1
if %28x%2B4%29%5E3=0=>x=-4,..... multiplicity 3
b)Determine whether graph crosses or touches the x-axis at each x-intercept:

For zeros with+even multiplicities, the graphs touch or are tangent to the x-axis at these x-values.
For zeros with odd multiplicities, the graphs cross or intersect the x-axis at these x-values.
x=-4 have an +even multiplicity => the graph will touch the x-axis
x=-1%2F2 have an odd multiplicity=> the graph will cross the x-axis

c)Determine the behavior of the graph near each x-intercept(zero):
Since the leading term of the polynomial (the term in the polynomial which contains the highest power of the variable) is -2x%5E4, the degree is 4, i.e. even, and the leading coefficient is -2, i.e. negative.
This means that f(x)→ -∞ as x→ -∞ , f(x)→ -∞ as x→ ∞


d)Determine the maximum number of turning point on the graph:
The maximum number of turning points of a polynomial function is always one less than the degree of the function.
This function f is a 4th degree polynomial function and has 3 turning points.

e)Determine the end behavior, that is finding the power function that the graph of
f resembles for large values of |x|:
If we expand we get
f%28x%29+=+-2x%5E4+-+25x%5E3+-+108x%5E2+-+176x+-+64
f%28x%29+=+-2x%5E4 ..... the dominating term


Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
Graph this:
graph%28300%2C300%2C-10%2C10%2C-50%2C25%2C2%28x%2B0.5%29%28x%2B4%29%5E3%29; graph%28300%2C300%2C-5%2C5%2C-5%2C5%2C2%28x%2B0.5%29%28x%2B4%29%5E3%29
By inspection, x=-4 is a root with multiplicity 3, and so is x=-0.5. Both of those make the parentheses 0, and they cross the x-axis.
-
Take the derivative of the function:
f'(x)=2(x+0.5)*3(x+4)^2+(x+4)^3(2)
as x approaches -4 from the either side, the derivative is negative, or the slope negative.
As x approaches 0.5 from either side, the slope is positive.
There is one turning point where the derivative is 0.
2(x+0.5)*3(x+4)^2+2(x+4)^3=0
divide both sides by (x+4)^2
6x+3+2(x+4)=0
8x+11=0
x=-1.375
y=-31.65
-
end behavior negative is (-x)^4 positive oo
and for positive is x^4 positive oo