Sketch the graph indicating the horizontal and vertical asym
Solution
13)
f(x)=(3x2+5x-12)/(x2-2x-15)
f(x)=((3x-4)(x+3))/((x-5)(x+3)) , domain (-,-3)U(-3,5)U(5,)
HA: y=3
VA: (x+3) cancels out
denominator=0
x-5=0
x=5
x intercept :(x+3) cancels out
numerator=0
3x-4=0
x=4/3
point is (4/3,0)
y intercept:x=0
y=(0+0-12)/(0-0-15)
y=4/5
point is (0,4/5)
RD means?
---------------------------------
14), domain (-,-3)U(-3,5)U(5,)
end behaviour:
lim[x->]f(x)
=lim[x->](3x2+5x-12)/(x2-2x-15)
=3
lim[x->-]f(x)
=lim[x->-](3x2+5x-12)/(x2-2x-15)
=3
at discontinuities:
at x =-3
limx->-3 f(x)
=limx->-3((3x-4)(x+3))/((x-5)(x+3))
=limx->-3(3x-4)/(x-5)
=(-9-4)/(-3-5)
=13/8
limx->5- f(x)
=limx->5-((3x-4)(x+3))/((x-5)(x+3))
=limx->5-(3x-4)/(x-5)
=-
limx->5+ f(x)
=limx->5+((3x-4)(x+3))/((x-5)(x+3))
=limx->5+(3x-4)/(x-5)
=
removable discontinuity at x =-3
infinate discontinuity at x =5
-----------------------------------
15)
(3x2+5x-12)/(x2-2x-15)=((3x-4)(x+3))/((x-5)(x+3))
(3x2+5x-12)/(x2-2x-15)=((1/3)(x-(4/3))(x+3))/((x-5)(x+3))
x...........................-3.......................4/3.....................5...................
f(x).............+........dne........+............0............-........dne.........+...................
(3x2+5x-12)/(x2-2x-15)>=0
x=(-,-3)U(-3,4/3]U(5,)

