https://docs.google.com/document/pub?id=1enrHRY8cOT5Phj1QrnlZvXPC-gscGcB6Mo83Z1zZhBo
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f(x)= (2x^2+3x)/e^x
A) no vert. Asymp. ( denom cannot = zero)
Horiz.asymp: use l'hopitals
Lim(x->inf) = inf/inf
= lim( 4x+3)/e^x -> inf/inf
= lim(4/e^x)
= 0
y= 0
B) to find inc.and dec, find y' by quotient rule.
Y' =[e^x(4x+3)- (2x^2+3x)*e^x]/ [e^(2x)]
= (-2x^2+x+3)/e^x=0
Solve -2x^2+x+3=0
-(2x-3)(x+1)=0
x=3/2 or -1
------(-1)-----(3/2)----- test the sign of y'
(-)............(+)...........(-)
Decreasing on (-inf, -1) and (3/2, inf)
Increasing on (-1,3/2)
C) min at (-1,? ); max at (3/2,?) find y values from the original function.
D) use the second deriv. To test for inflection points and concavity.
Y" = (2x^2-5x-2)/e^x by quotient rule.
Set equal to zero, solve by quadratic formula.
X=[ 5+/-sqr(41)]/4
x= -.35 or 2.85
Test for concavity
--------(-.35)-----(2.85)-----
(+).... .........(-).... .........(+)
up..............down.........up
(-inf, -.35). (-.35,2.85).....(2.85, inf)
Infl points at x= -.35 and 2.85
Find y values from the original function.
Double check all values on your calculator.
Hoping this helps!
A) no vert. Asymp. ( denom cannot = zero)
Horiz.asymp: use l'hopitals
Lim(x->inf) = inf/inf
= lim( 4x+3)/e^x -> inf/inf
= lim(4/e^x)
= 0
y= 0
B) to find inc.and dec, find y' by quotient rule.
Y' =[e^x(4x+3)- (2x^2+3x)*e^x]/ [e^(2x)]
= (-2x^2+x+3)/e^x=0
Solve -2x^2+x+3=0
-(2x-3)(x+1)=0
x=3/2 or -1
------(-1)-----(3/2)----- test the sign of y'
(-)............(+)...........(-)
Decreasing on (-inf, -1) and (3/2, inf)
Increasing on (-1,3/2)
C) min at (-1,? ); max at (3/2,?) find y values from the original function.
D) use the second deriv. To test for inflection points and concavity.
Y" = (2x^2-5x-2)/e^x by quotient rule.
Set equal to zero, solve by quadratic formula.
X=[ 5+/-sqr(41)]/4
x= -.35 or 2.85
Test for concavity
--------(-.35)-----(2.85)-----
(+).... .........(-).... .........(+)
up..............down.........up
(-inf, -.35). (-.35,2.85).....(2.85, inf)
Infl points at x= -.35 and 2.85
Find y values from the original function.
Double check all values on your calculator.
Hoping this helps!
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47 R
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Not so much