Calculus Examples

Find the Absolute Max and Min over the Interval f(x)=1/2x^4-2/3x^3-2x^2+3 on -3 , 3
f(x)=12x4-23x3-2x2+3f(x)=12x423x32x2+3 on -3 , 3
Step 1
Find the critical points.
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Step 1.1
Find the first derivative.
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Step 1.1.1
Find the first derivative.
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Step 1.1.1.1
By the Sum Rule, the derivative of 12x4-23x3-2x2+3 with respect to x is ddx[12x4]+ddx[-23x3]+ddx[-2x2]+ddx[3].
ddx[12x4]+ddx[-23x3]+ddx[-2x2]+ddx[3]
Step 1.1.1.2
Evaluate ddx[12x4].
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Step 1.1.1.2.1
Since 12 is constant with respect to x, the derivative of 12x4 with respect to x is 12ddx[x4].
12ddx[x4]+ddx[-23x3]+ddx[-2x2]+ddx[3]
Step 1.1.1.2.2
Differentiate using the Power Rule which states that ddx[xn] is nxn-1 where n=4.
12(4x3)+ddx[-23x3]+ddx[-2x2]+ddx[3]
Step 1.1.1.2.3
Combine 4 and 12.
42x3+ddx[-23x3]+ddx[-2x2]+ddx[3]
Step 1.1.1.2.4
Combine 42 and x3.
4x32+ddx[-23x3]+ddx[-2x2]+ddx[3]
Step 1.1.1.2.5
Cancel the common factor of 4 and 2.
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Step 1.1.1.2.5.1
Factor 2 out of 4x3.
2(2x3)2+ddx[-23x3]+ddx[-2x2]+ddx[3]
Step 1.1.1.2.5.2
Cancel the common factors.
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Step 1.1.1.2.5.2.1
Factor 2 out of 2.
2(2x3)2(1)+ddx[-23x3]+ddx[-2x2]+ddx[3]
Step 1.1.1.2.5.2.2
Cancel the common factor.
2(2x3)21+ddx[-23x3]+ddx[-2x2]+ddx[3]
Step 1.1.1.2.5.2.3
Rewrite the expression.
2x31+ddx[-23x3]+ddx[-2x2]+ddx[3]
Step 1.1.1.2.5.2.4
Divide 2x3 by 1.
2x3+ddx[-23x3]+ddx[-2x2]+ddx[3]
2x3+ddx[-23x3]+ddx[-2x2]+ddx[3]
2x3+ddx[-23x3]+ddx[-2x2]+ddx[3]
2x3+ddx[-23x3]+ddx[-2x2]+ddx[3]
Step 1.1.1.3
Evaluate ddx[-23x3].
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Step 1.1.1.3.1
Since -23 is constant with respect to x, the derivative of -23x3 with respect to x is -23ddx[x3].
2x3-23ddx[x3]+ddx[-2x2]+ddx[3]
Step 1.1.1.3.2
Differentiate using the Power Rule which states that ddx[xn] is nxn-1 where n=3.
2x3-23(3x2)+ddx[-2x2]+ddx[3]
Step 1.1.1.3.3
Multiply 3 by -1.
2x3-3(23)x2+ddx[-2x2]+ddx[3]
Step 1.1.1.3.4
Combine -3 and 23.
2x3+-323x2+ddx[-2x2]+ddx[3]
Step 1.1.1.3.5
Multiply -3 by 2.
2x3+-63x2+ddx[-2x2]+ddx[3]
Step 1.1.1.3.6
Combine -63 and x2.
2x3+-6x23+ddx[-2x2]+ddx[3]
Step 1.1.1.3.7
Cancel the common factor of -6 and 3.
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Step 1.1.1.3.7.1
Factor 3 out of -6x2.
2x3+3(-2x2)3+ddx[-2x2]+ddx[3]
Step 1.1.1.3.7.2
Cancel the common factors.
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Step 1.1.1.3.7.2.1
Factor 3 out of 3.
2x3+3(-2x2)3(1)+ddx[-2x2]+ddx[3]
Step 1.1.1.3.7.2.2
Cancel the common factor.
2x3+3(-2x2)31+ddx[-2x2]+ddx[3]
Step 1.1.1.3.7.2.3
Rewrite the expression.
2x3+-2x21+ddx[-2x2]+ddx[3]
Step 1.1.1.3.7.2.4
Divide -2x2 by 1.
2x3-2x2+ddx[-2x2]+ddx[3]
2x3-2x2+ddx[-2x2]+ddx[3]
2x3-2x2+ddx[-2x2]+ddx[3]
2x3-2x2+ddx[-2x2]+ddx[3]
Step 1.1.1.4
Evaluate ddx[-2x2].
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Step 1.1.1.4.1
Since -2 is constant with respect to x, the derivative of -2x2 with respect to x is -2ddx[x2].
2x3-2x2-2ddx[x2]+ddx[3]
Step 1.1.1.4.2
Differentiate using the Power Rule which states that ddx[xn] is nxn-1 where n=2.
2x3-2x2-2(2x)+ddx[3]
Step 1.1.1.4.3
Multiply 2 by -2.
2x3-2x2-4x+ddx[3]
2x3-2x2-4x+ddx[3]
Step 1.1.1.5
Differentiate using the Constant Rule.
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Step 1.1.1.5.1
Since 3 is constant with respect to x, the derivative of 3 with respect to x is 0.
2x3-2x2-4x+0
Step 1.1.1.5.2
Add 2x3-2x2-4x and 0.
f(x)=2x3-2x2-4x
f(x)=2x3-2x2-4x
f(x)=2x3-2x2-4x
Step 1.1.2
The first derivative of f(x) with respect to x is 2x3-2x2-4x.
2x3-2x2-4x
2x3-2x2-4x
Step 1.2
Set the first derivative equal to 0 then solve the equation 2x3-2x2-4x=0.
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Step 1.2.1
Set the first derivative equal to 0.
2x3-2x2-4x=0
Step 1.2.2
Factor the left side of the equation.
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Step 1.2.2.1
Factor 2x out of 2x3-2x2-4x.
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Step 1.2.2.1.1
Factor 2x out of 2x3.
2x(x2)-2x2-4x=0
Step 1.2.2.1.2
Factor 2x out of -2x2.
2x(x2)+2x(-x)-4x=0
Step 1.2.2.1.3
Factor 2x out of -4x.
2x(x2)+2x(-x)+2x(-2)=0
Step 1.2.2.1.4
Factor 2x out of 2x(x2)+2x(-x).
2x(x2-x)+2x(-2)=0
Step 1.2.2.1.5
Factor 2x out of 2x(x2-x)+2x(-2).
2x(x2-x-2)=0
2x(x2-x-2)=0
Step 1.2.2.2
Factor.
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Step 1.2.2.2.1
Factor x2-x-2 using the AC method.
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Step 1.2.2.2.1.1
Consider the form x2+bx+c. Find a pair of integers whose product is c and whose sum is b. In this case, whose product is -2 and whose sum is -1.
-2,1
Step 1.2.2.2.1.2
Write the factored form using these integers.
2x((x-2)(x+1))=0
2x((x-2)(x+1))=0
Step 1.2.2.2.2
Remove unnecessary parentheses.
2x(x-2)(x+1)=0
2x(x-2)(x+1)=0
2x(x-2)(x+1)=0
Step 1.2.3
If any individual factor on the left side of the equation is equal to 0, the entire expression will be equal to 0.
x=0
x-2=0
x+1=0
Step 1.2.4
Set x equal to 0.
x=0
Step 1.2.5
Set x-2 equal to 0 and solve for x.
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Step 1.2.5.1
Set x-2 equal to 0.
x-2=0
Step 1.2.5.2
Add 2 to both sides of the equation.
x=2
x=2
Step 1.2.6
Set x+1 equal to 0 and solve for x.
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Step 1.2.6.1
Set x+1 equal to 0.
x+1=0
Step 1.2.6.2
Subtract 1 from both sides of the equation.
x=-1
x=-1
Step 1.2.7
The final solution is all the values that make 2x(x-2)(x+1)=0 true.
x=0,2,-1
x=0,2,-1
Step 1.3
Find the values where the derivative is undefined.
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Step 1.3.1
The domain of the expression is all real numbers except where the expression is undefined. In this case, there is no real number that makes the expression undefined.
Step 1.4
Evaluate 12x4-23x3-2x2+3 at each x value where the derivative is 0 or undefined.
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Step 1.4.1
Evaluate at x=0.
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Step 1.4.1.1
Substitute 0 for x.
12(0)4-23(0)3-2(0)2+3
Step 1.4.1.2
Simplify.
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Step 1.4.1.2.1
Simplify each term.
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Step 1.4.1.2.1.1
Raising 0 to any positive power yields 0.
120-23(0)3-2(0)2+3
Step 1.4.1.2.1.2
Multiply 12 by 0.
0-23(0)3-2(0)2+3
Step 1.4.1.2.1.3
Raising 0 to any positive power yields 0.
0-230-2(0)2+3
Step 1.4.1.2.1.4
Multiply -230.
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Step 1.4.1.2.1.4.1
Multiply 0 by -1.
0+0(23)-2(0)2+3
Step 1.4.1.2.1.4.2
Multiply 0 by 23.
0+0-2(0)2+3
0+0-2(0)2+3
Step 1.4.1.2.1.5
Raising 0 to any positive power yields 0.
0+0-20+3
Step 1.4.1.2.1.6
Multiply -2 by 0.
0+0+0+3
0+0+0+3
Step 1.4.1.2.2
Simplify by adding numbers.
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Step 1.4.1.2.2.1
Add 0 and 0.
0+0+3
Step 1.4.1.2.2.2
Add 0 and 0.
0+3
Step 1.4.1.2.2.3
Add 0 and 3.
3
3
3
3
Step 1.4.2
Evaluate at x=2.
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Step 1.4.2.1
Substitute 2 for x.
12(2)4-23(2)3-2(2)2+3
Step 1.4.2.2
Simplify.
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Step 1.4.2.2.1
Simplify each term.
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Step 1.4.2.2.1.1
Cancel the common factor of 2.
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Step 1.4.2.2.1.1.1
Factor 2 out of (2)4.
12(223)-23(2)3-2(2)2+3
Step 1.4.2.2.1.1.2
Cancel the common factor.
12(223)-23(2)3-2(2)2+3
Step 1.4.2.2.1.1.3
Rewrite the expression.
23-23(2)3-2(2)2+3
23-23(2)3-2(2)2+3
Step 1.4.2.2.1.2
Raise 2 to the power of 3.
8-23(2)3-2(2)2+3
Step 1.4.2.2.1.3
Raise 2 to the power of 3.
8-238-2(2)2+3
Step 1.4.2.2.1.4
Multiply -238.
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Step 1.4.2.2.1.4.1
Multiply 8 by -1.
8-8(23)-2(2)2+3
Step 1.4.2.2.1.4.2
Combine -8 and 23.
8+-823-2(2)2+3
Step 1.4.2.2.1.4.3
Multiply -8 by 2.
8+-163-2(2)2+3
8+-163-2(2)2+3
Step 1.4.2.2.1.5
Move the negative in front of the fraction.
8-163-2(2)2+3
Step 1.4.2.2.1.6
Raise 2 to the power of 2.
8-163-24+3
Step 1.4.2.2.1.7
Multiply -2 by 4.
8-163-8+3
8-163-8+3
Step 1.4.2.2.2
Find the common denominator.
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Step 1.4.2.2.2.1
Write 8 as a fraction with denominator 1.
81-163-8+3
Step 1.4.2.2.2.2
Multiply 81 by 33.
8133-163-8+3
Step 1.4.2.2.2.3
Multiply 81 by 33.
833-163-8+3
Step 1.4.2.2.2.4
Write -8 as a fraction with denominator 1.
833-163+-81+3
Step 1.4.2.2.2.5
Multiply -81 by 33.
833-163+-8133+3
Step 1.4.2.2.2.6
Multiply -81 by 33.
833-163+-833+3
Step 1.4.2.2.2.7
Write 3 as a fraction with denominator 1.
833-163+-833+31
Step 1.4.2.2.2.8
Multiply 31 by 33.
833-163+-833+3133
Step 1.4.2.2.2.9
Multiply 31 by 33.
833-163+-833+333
833-163+-833+333
Step 1.4.2.2.3
Combine the numerators over the common denominator.
83-16-83+333
Step 1.4.2.2.4
Simplify each term.
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Step 1.4.2.2.4.1
Multiply 8 by 3.
24-16-83+333
Step 1.4.2.2.4.2
Multiply -8 by 3.
24-16-24+333
Step 1.4.2.2.4.3
Multiply 3 by 3.
24-16-24+93
24-16-24+93
Step 1.4.2.2.5
Simplify the expression.
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Step 1.4.2.2.5.1
Subtract 16 from 24.
8-24+93
Step 1.4.2.2.5.2
Subtract 24 from 8.
-16+93
Step 1.4.2.2.5.3
Add -16 and 9.
-73
Step 1.4.2.2.5.4
Move the negative in front of the fraction.
-73
-73
-73
-73
Step 1.4.3
Evaluate at x=-1.
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Step 1.4.3.1
Substitute -1 for x.
12(-1)4-23(-1)3-2(-1)2+3
Step 1.4.3.2
Simplify.
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Step 1.4.3.2.1
Simplify each term.
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Step 1.4.3.2.1.1
Raise -1 to the power of 4.
121-23(-1)3-2(-1)2+3
Step 1.4.3.2.1.2
Multiply 12 by 1.
12-23(-1)3-2(-1)2+3
Step 1.4.3.2.1.3
Multiply -1 by (-1)3 by adding the exponents.
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Step 1.4.3.2.1.3.1
Move (-1)3.
12+(-1)3-123-2(-1)2+3
Step 1.4.3.2.1.3.2
Multiply (-1)3 by -1.
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Step 1.4.3.2.1.3.2.1
Raise -1 to the power of 1.
12+(-1)3(-1)123-2(-1)2+3
Step 1.4.3.2.1.3.2.2
Use the power rule aman=am+n to combine exponents.
12+(-1)3+123-2(-1)2+3
12+(-1)3+123-2(-1)2+3
Step 1.4.3.2.1.3.3
Add 3 and 1.
12+(-1)423-2(-1)2+3
12+(-1)423-2(-1)2+3
Step 1.4.3.2.1.4
Raise -1 to the power of 4.
12+1(23)-2(-1)2+3
Step 1.4.3.2.1.5
Multiply 23 by 1.
12+23-2(-1)2+3
Step 1.4.3.2.1.6
Raise -1 to the power of 2.
12+23-21+3
Step 1.4.3.2.1.7
Multiply -2 by 1.
12+23-2+3
12+23-2+3
Step 1.4.3.2.2
Find the common denominator.
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Step 1.4.3.2.2.1
Multiply 12 by 33.
1233+23-2+3
Step 1.4.3.2.2.2
Multiply 12 by 33.
323+23-2+3
Step 1.4.3.2.2.3
Multiply 23 by 22.
323+2322-2+3
Step 1.4.3.2.2.4
Multiply 23 by 22.
323+2232-2+3
Step 1.4.3.2.2.5
Write -2 as a fraction with denominator 1.
323+2232+-21+3
Step 1.4.3.2.2.6
Multiply -21 by 66.
323+2232+-2166+3
Step 1.4.3.2.2.7
Multiply -21 by 66.
323+2232+-266+3
Step 1.4.3.2.2.8
Write 3 as a fraction with denominator 1.
323+2232+-266+31
Step 1.4.3.2.2.9
Multiply 31 by 66.
323+2232+-266+3166
Step 1.4.3.2.2.10
Multiply 31 by 66.
323+2232+-266+366
Step 1.4.3.2.2.11
Multiply 2 by 3.
36+2232+-266+366
Step 1.4.3.2.2.12
Reorder the factors of 32.
36+2223+-266+366
Step 1.4.3.2.2.13
Multiply 2 by 3.
36+226+-266+366
36+226+-266+366
Step 1.4.3.2.3
Combine the numerators over the common denominator.
3+22-26+366
Step 1.4.3.2.4
Simplify each term.
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Step 1.4.3.2.4.1
Multiply 2 by 2.
3+4-26+366
Step 1.4.3.2.4.2
Multiply -2 by 6.
3+4-12+366
Step 1.4.3.2.4.3
Multiply 3 by 6.
3+4-12+186
3+4-12+186
Step 1.4.3.2.5
Simplify by adding and subtracting.
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Step 1.4.3.2.5.1
Add 3 and 4.
7-12+186
Step 1.4.3.2.5.2
Subtract 12 from 7.
-5+186
Step 1.4.3.2.5.3
Add -5 and 18.
136
136
136
136
Step 1.4.4
List all of the points.
(0,3),(2,-73),(-1,136)
(0,3),(2,-73),(-1,136)
(0,3),(2,-73),(-1,136)
Step 2
Evaluate at the included endpoints.
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Step 2.1
Evaluate at x=-3.
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Step 2.1.1
Substitute -3 for x.
12(-3)4-23(-3)3-2(-3)2+3
Step 2.1.2
Simplify.
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Step 2.1.2.1
Simplify each term.
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Step 2.1.2.1.1
Raise -3 to the power of 4.
1281-23(-3)3-2(-3)2+3
Step 2.1.2.1.2
Combine 12 and 81.
812-23(-3)3-2(-3)2+3
Step 2.1.2.1.3
Raise -3 to the power of 3.
812-23-27-2(-3)2+3
Step 2.1.2.1.4
Cancel the common factor of 3.
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Step 2.1.2.1.4.1
Move the leading negative in -23 into the numerator.
812+-23-27-2(-3)2+3
Step 2.1.2.1.4.2
Factor 3 out of -27.
812+-23(3(-9))-2(-3)2+3
Step 2.1.2.1.4.3
Cancel the common factor.
812+-23(3-9)-2(-3)2+3
Step 2.1.2.1.4.4
Rewrite the expression.
812-2-9-2(-3)2+3
812-2-9-2(-3)2+3
Step 2.1.2.1.5
Multiply -2 by -9.
812+18-2(-3)2+3
Step 2.1.2.1.6
Raise -3 to the power of 2.
812+18-29+3
Step 2.1.2.1.7
Multiply -2 by 9.
812+18-18+3
812+18-18+3
Step 2.1.2.2
Find the common denominator.
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Step 2.1.2.2.1
Write 18 as a fraction with denominator 1.
812+181-18+3
Step 2.1.2.2.2
Multiply 181 by 22.
812+18122-18+3
Step 2.1.2.2.3
Multiply 181 by 22.
812+1822-18+3
Step 2.1.2.2.4
Write -18 as a fraction with denominator 1.
812+1822+-181+3
Step 2.1.2.2.5
Multiply -181 by 22.
812+1822+-18122+3
Step 2.1.2.2.6
Multiply -181 by 22.
812+1822+-1822+3
Step 2.1.2.2.7
Write 3 as a fraction with denominator 1.
812+1822+-1822+31
Step 2.1.2.2.8
Multiply 31 by 22.
812+1822+-1822+3122
Step 2.1.2.2.9
Multiply 31 by 22.
812+1822+-1822+322
812+1822+-1822+322
Step 2.1.2.3
Combine the numerators over the common denominator.
81+182-182+322
Step 2.1.2.4
Simplify each term.
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Step 2.1.2.4.1
Multiply 18 by 2.
81+36-182+322
Step 2.1.2.4.2
Multiply -18 by 2.
81+36-36+322
Step 2.1.2.4.3
Multiply 3 by 2.
81+36-36+62
81+36-36+62
Step 2.1.2.5
Simplify by adding and subtracting.
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Step 2.1.2.5.1
Add 81 and 36.
117-36+62
Step 2.1.2.5.2
Subtract 36 from 117.
81+62
Step 2.1.2.5.3
Add 81 and 6.
872
872
872
872
Step 2.2
Evaluate at x=3.
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Step 2.2.1
Substitute 3 for x.
12(3)4-23(3)3-2(3)2+3
Step 2.2.2
Simplify.
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Step 2.2.2.1
Simplify each term.
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Step 2.2.2.1.1
Raise 3 to the power of 4.
1281-23(3)3-2(3)2+3
Step 2.2.2.1.2
Combine 12 and 81.
812-23(3)3-2(3)2+3
Step 2.2.2.1.3
Cancel the common factor of 3.
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Step 2.2.2.1.3.1
Move the leading negative in -23 into the numerator.
812+-23(3)3-2(3)2+3
Step 2.2.2.1.3.2
Factor 3 out of (3)3.
812+-23(332)-2(3)2+3
Step 2.2.2.1.3.3
Cancel the common factor.
812+-23(332)-2(3)2+3
Step 2.2.2.1.3.4
Rewrite the expression.
812-232-2(3)2+3
812-232-2(3)2+3
Step 2.2.2.1.4
Raise 3 to the power of 2.
812-29-2(3)2+3
Step 2.2.2.1.5
Multiply -2 by 9.
812-18-2(3)2+3
Step 2.2.2.1.6
Raise 3 to the power of 2.
812-18-29+3
Step 2.2.2.1.7
Multiply -2 by 9.
812-18-18+3
812-18-18+3
Step 2.2.2.2
Find the common denominator.
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Step 2.2.2.2.1
Write -18 as a fraction with denominator 1.
812+-181-18+3
Step 2.2.2.2.2
Multiply -181 by 22.
812+-18122-18+3
Step 2.2.2.2.3
Multiply -181 by 22.
812+-1822-18+3
Step 2.2.2.2.4
Write -18 as a fraction with denominator 1.
812+-1822+-181+3
Step 2.2.2.2.5
Multiply -181 by 22.
812+-1822+-18122+3
Step 2.2.2.2.6
Multiply -181 by 22.
812+-1822+-1822+3
Step 2.2.2.2.7
Write 3 as a fraction with denominator 1.
812+-1822+-1822+31
Step 2.2.2.2.8
Multiply 31 by 22.
812+-1822+-1822+3122
Step 2.2.2.2.9
Multiply 31 by 22.
812+-1822+-1822+322
812+-1822+-1822+322
Step 2.2.2.3
Combine the numerators over the common denominator.
81-182-182+322
Step 2.2.2.4
Simplify each term.
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Step 2.2.2.4.1
Multiply -18 by 2.
81-36-182+322
Step 2.2.2.4.2
Multiply -18 by 2.
81-36-36+322
Step 2.2.2.4.3
Multiply 3 by 2.
81-36-36+62
81-36-36+62
Step 2.2.2.5
Simplify by adding and subtracting.
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Step 2.2.2.5.1
Subtract 36 from 81.
45-36+62
Step 2.2.2.5.2
Subtract 36 from 45.
9+62
Step 2.2.2.5.3
Add 9 and 6.
152
152
152
152
Step 2.3
List all of the points.
(-3,872),(3,152)
(-3,872),(3,152)
Step 3
Compare the f(x) values found for each value of x in order to determine the absolute maximum and minimum over the given interval. The maximum will occur at the highest f(x) value and the minimum will occur at the lowest f(x) value.
Absolute Maximum: (-3,872)
Absolute Minimum: (2,-73)
Step 4
 [x2  12  π  xdx ]