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Can I please have answers for the following calculus questions?
Just looking to check my answers as the methods done.
(1)
If
f(x)= {x^2 if x<(or equal to)3
{mx+b if x >3
find the values of m and b that make f differentiable everywhere.
(2)
Find the derivative of the function
g(x)=(1x^2 -4x-1)e^x
g'(x)= ?
(3)
let f(x)=(x^2+8x+16)/(6x+24)
f'(5)=?
f''(5)= ?
(4)
Let f(x)= sin(x^5)
f'(x)=?
f'(1)=?
(5)
Let f(x)=2e^(xsinx)
f'(x)=?
(6)
Consider the function f(x)=2x^3+18x^2-162x+5, -9<(or equal to)x<(or equal to)4
Absolute minimum value?
Absolute maximum value?
(7)
Find the x coordinateof the absolute maximum for the function
f(x)=11x-5xln(x), x>0
(8)
Find an equation of the tangent line to the curve y=-1-2x-3x^2 at (1,-6)
y=?
(9)
Use implicit differentiation to find the slope of the tangent line to the curve 3x^2-3xy+3y^3=-192 at the point (-4,-4)
m=?
1 Answer
- TomLv 58 years agoFavorite Answer
(1)
If
f(x)= {x^2 if x<= 3
.......{mx+b if x >3
f(x) continuous at x=3 => 3^2 = 3m +b
differentiable at x=3 => 2(3) = m = 6, so b = -9
(2)
Find the derivative of the function
g(x)=(x^2 -4x-1)e^x
g'(x)= (x^2 -4x -1)e^x + (2x -4)e^x by product rule,
= (x^2 -2x -5)e^x
(3)
let f(x)=(x^2+8x+16)/(6x+24)
= (x + 4)^2/ 6(x + 4) = (x + 4)/6 .. x ≠ -4
f '(5)= 1/6
f ''(5)= 0
(4)
Let f(x)= sin(x^5)
f '(x)= -(5x^4)cos(x^5) ... chain rule
f '(1)= -5.cos(1 radian) = -2.702
(5)
Let f(x)=2e^(xsinx)
f '(x)= 2[sinx -xcosx]e^(xsinx)
(6)
Consider the function
f(x)=2x^3 +18x^2 -162x +5, -9<=x<=4
f '(x) = 6x^2 +36x -162 = 6[x^2 +6x -27] = 6(x +9)(x -3)
SPs are at x = -9 and x = 3 both in domain interval..
f ''(x) = 12x + 36 with f ''(-9) <0 so f(-9) a local maxima and
f ''(3) > 0 a local minima
boundary values are f(3) = -265 a minima and f(4) = -227
Absolute minimum value?
f(3) = -265
Absolute maximum value?
f(-9) = 1463
(7)
Find the x coordinate of the absolute maximum for the function
f(x) =11x -5x.ln(x), x>0
f '(x) = 11 - 5[1 +lnx] = 0 => lnx = 6/5
f ''(x) = -5(1/x) < 0 so local maximum
so x_max = e^(6/5) = 3.320
(8)
Find an equation of the tangent line to the curve y = -1 -2x -3x^2 at (1,-6)
dy/dx = -2 -6x
slope (y = mx + c) = m = -2 -6(1) = -8
so y = -8x +c
-6 = -8 +c => c = 2
y = -8x +2
(9)
Use implicit differentiation to find the slope of the tangent line to the curve:
3x^2 -3xy +3y^3 = -192 at the point (-4,-4)
6x -3xy' -3y +9y'y^2 = 0 but y' = m at given point
6(-4) -3(-4)m -3(-4) +9m(-4)^2 = 0
-24 +12m +12 +9*16m = 0
-2 + m +1 +12m = 0
m = 1/13
2 days ago - 2