SOLUTION: f(x)= x-5 (divied by) 4-x^2 x - intercept(s): y - intercept: Vertical Asymptote(s): Horizontal Asymptote(s): Domain: End-Behavior: Intervals of Increasing/Decre

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: f(x)= x-5 (divied by) 4-x^2 x - intercept(s): y - intercept: Vertical Asymptote(s): Horizontal Asymptote(s): Domain: End-Behavior: Intervals of Increasing/Decre      Log On


   



Question 1177854: f(x)= x-5 (divied by) 4-x^2
x - intercept(s):
y - intercept:
Vertical Asymptote(s):
Horizontal Asymptote(s):
Domain:
End-Behavior:
Intervals of Increasing/Decreasing:

Intervals of Positive/Negative:

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

f%28x%29=+%28x-5%29%2F%284-x%5E2%29
x - intercept(s):
set f%28x%29=0+
%28x-5%29%2F%284-x%5E2%29=0..........since denominator cannot be zero, use numerator only
%28x-5%29=0 =>x=5
x - intercept is at (5,0)

y - intercept:
set x=0+
f%28x%29=+%280-5%29%2F%284-0%5E2%29
f%28x%29=+-5%2F4
y - intercept is at (0,-5%2F4)

Vertical Asymptote(s):
f%28x%29=%28x-5%29%2F%284-x%5E2%29.......set denominator equal to zero
%284-x%5E2%29=0=>4=x%5E2=>+x=2 and x=-2

Horizontal Asymptote(s):
f%28x%29=+%28x-5%29%2F%284-x%5E2%29
Degree of numerator is less than degree of denominator: horizontal asymptote at f%28x%29+=+0.

Domain:
{ x element R : x%3C%3E-2+and x%3C%3E2 }
or
-2%3Cx%3C2

range:
f%28x%29=y
y=+%28x-5%29%2F%284-x%5E2%29
Rewrite the above equation for x in standard form and solve using quadratic formulae
y%284-x%5E2%29=+%28x-5%29
4y-yx%5E2=+x-5
0=+yx%5E2%2Bx-4y-5
0=+yx%5E2%2Bx-%284y%2B5%29-> a=y, b=1, c=-(4y+5)
Find the discriminant to the above equation
b%5E2-4ac=1-4%2Ay%28-%284y%2B5%29%29
.............=1%2B16%2Ay%5E2%2B20y
.............=16%2Ay%5E2%2B20y+%2B1
Using the quadratic formulas, the above equation gives the solutions
x%5B1%2C2%5D=%281%2B-sqrt%2816%2Ay%5E2%2B20y+%2B1%29%29%2F2y
The solutions x%5B1%2C2%5D are real if 16%2Ay%5E2%2B20y+%2B1++%3E=++0 and y+0.
Hence we need to solve the inequality
16%2Ay%5E2%2B20y+%2B1+%3E=+0 and solution will be
y%3E=+%28sqrt%2821%29+-+5%29%2F8
y%3C=+%28-5+-+sqrt%2821%29%29%2F8

End-Behavior:
function end-behavior of %28x-5%29%2F%284-x%5E2%29:
as x-%3Einfinity, f%28x%29+-%3E0, and
as x-%3E-infinity,f%28x%29-%3E0

Intervals of Increasing/Decreasing:
If f' %28x+%29%3E0 then f+%28x+%29 is increasing
If f' %28x+%29%3C0 then f+%28x+%29+is decreasing
f%28x%29=%28x-5%29%2F%284-x%5E2%29...derivate
f'%28x%29+=+%28x%5E2+-+10+x+%2B+4%29%2F%28x%5E2+-+4%29%5E2
Increasing -infinity+%3C+x+%3C-2, and -2%3C+x+%3C-sqrt%2821%29%2B5,
Decreasing:-sqrt%2821%29%2B5+%3C+x+%3C+2

Intervals of Positive/Negative:
positive when +-infinity+%3C+x%3C+-2+ U 2%3C+x+%3C+infinity+
negative when -2%3C+x%3C+2
download