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Calculus Examples
(x2-1)3(x2−1)3
Step 1
Step 1.1
Differentiate using the chain rule, which states that ddx[f(g(x))] is f′(g(x))g′(x) where f(x)=x3 and g(x)=x2-1.
Step 1.1.1
To apply the Chain Rule, set u as x2-1.
ddu[u3]ddx[x2-1]
Step 1.1.2
Differentiate using the Power Rule which states that ddu[un] is nun-1 where n=3.
3u2ddx[x2-1]
Step 1.1.3
Replace all occurrences of u with x2-1.
3(x2-1)2ddx[x2-1]
3(x2-1)2ddx[x2-1]
Step 1.2
Differentiate.
Step 1.2.1
By the Sum Rule, the derivative of x2-1 with respect to x is ddx[x2]+ddx[-1].
3(x2-1)2(ddx[x2]+ddx[-1])
Step 1.2.2
Differentiate using the Power Rule which states that ddx[xn] is nxn-1 where n=2.
3(x2-1)2(2x+ddx[-1])
Step 1.2.3
Since -1 is constant with respect to x, the derivative of -1 with respect to x is 0.
3(x2-1)2(2x+0)
Step 1.2.4
Simplify the expression.
Step 1.2.4.1
Add 2x and 0.
3(x2-1)2(2x)
Step 1.2.4.2
Multiply 2 by 3.
6(x2-1)2x
Step 1.2.4.3
Reorder the factors of 6(x2-1)2x.
6x(x2-1)2
6x(x2-1)2
6x(x2-1)2
6x(x2-1)2
Step 2
Step 2.1
Since 6 is constant with respect to x, the derivative of 6x(x2-1)2 with respect to x is 6ddx[x(x2-1)2].
f′′(x)=6ddx(x(x2-1)2)
Step 2.2
Differentiate using the Product Rule which states that ddx[f(x)g(x)] is f(x)ddx[g(x)]+g(x)ddx[f(x)] where f(x)=x and g(x)=(x2-1)2.
f′′(x)=6(xddx((x2-1)2)+(x2-1)2ddx(x))
Step 2.3
Differentiate using the chain rule, which states that ddx[f(g(x))] is f′(g(x))g′(x) where f(x)=x2 and g(x)=x2-1.
Step 2.3.1
To apply the Chain Rule, set u as x2-1.
f′′(x)=6(x(ddu(u2)ddx(x2-1))+(x2-1)2ddx(x))
Step 2.3.2
Differentiate using the Power Rule which states that ddu[un] is nun-1 where n=2.
f′′(x)=6(x(2uddx(x2-1))+(x2-1)2ddx(x))
Step 2.3.3
Replace all occurrences of u with x2-1.
f′′(x)=6(x(2(x2-1)ddx(x2-1))+(x2-1)2ddx(x))
f′′(x)=6(x(2(x2-1)ddx(x2-1))+(x2-1)2ddx(x))
Step 2.4
Differentiate.
Step 2.4.1
By the Sum Rule, the derivative of x2-1 with respect to x is ddx[x2]+ddx[-1].
f′′(x)=6(x(2(x2-1)(ddx(x2)+ddx(-1)))+(x2-1)2ddx(x))
Step 2.4.2
Differentiate using the Power Rule which states that ddx[xn] is nxn-1 where n=2.
f′′(x)=6(x(2(x2-1)(2x+ddx(-1)))+(x2-1)2ddx(x))
Step 2.4.3
Since -1 is constant with respect to x, the derivative of -1 with respect to x is 0.
f′′(x)=6(x(2(x2-1)(2x+0))+(x2-1)2ddx(x))
Step 2.4.4
Simplify the expression.
Step 2.4.4.1
Add 2x and 0.
f′′(x)=6(x(2(x2-1)(2x))+(x2-1)2ddx(x))
Step 2.4.4.2
Multiply 2 by 2.
f′′(x)=6(x(4(x2-1)x)+(x2-1)2ddx(x))
f′′(x)=6(x(4(x2-1)x)+(x2-1)2ddx(x))
f′′(x)=6(x(4(x2-1)x)+(x2-1)2ddx(x))
Step 2.5
Raise x to the power of 1.
f′′(x)=6(x⋅x(4(x2-1))+(x2-1)2ddx(x))
Step 2.6
Raise x to the power of 1.
f′′(x)=6(x⋅x(4(x2-1))+(x2-1)2ddx(x))
Step 2.7
Use the power rule aman=am+n to combine exponents.
f′′(x)=6(x1+1(4(x2-1))+(x2-1)2ddx(x))
Step 2.8
Add 1 and 1.
f′′(x)=6(x2(4(x2-1))+(x2-1)2ddx(x))
Step 2.9
Differentiate using the Power Rule which states that ddx[xn] is nxn-1 where n=1.
f′′(x)=6(x2(4(x2-1))+(x2-1)2⋅1)
Step 2.10
Multiply (x2-1)2 by 1.
f′′(x)=6(x2(4(x2-1))+(x2-1)2)
Step 2.11
Simplify.
Step 2.11.1
Apply the distributive property.
f′′(x)=6(x2(4x2+4⋅-1)+(x2-1)2)
Step 2.11.2
Apply the distributive property.
f′′(x)=6(x2(4x2)+x2(4⋅-1)+(x2-1)2)
Step 2.11.3
Apply the distributive property.
f′′(x)=6(x2(4x2))+6(x2(4⋅-1))+6(x2-1)2
Step 2.11.4
Combine terms.
Step 2.11.4.1
Multiply x2 by x2 by adding the exponents.
Step 2.11.4.1.1
Move x2.
f′′(x)=6(x2x2⋅4)+6(x2(4⋅-1))+6(x2-1)2
Step 2.11.4.1.2
Use the power rule aman=am+n to combine exponents.
f′′(x)=6(x2+2⋅4)+6(x2(4⋅-1))+6(x2-1)2
Step 2.11.4.1.3
Add 2 and 2.
f′′(x)=6(x4⋅4)+6(x2(4⋅-1))+6(x2-1)2
f′′(x)=6(x4⋅4)+6(x2(4⋅-1))+6(x2-1)2
Step 2.11.4.2
Move 4 to the left of x4.
f′′(x)=6(4⋅x4)+6(x2(4⋅-1))+6(x2-1)2
Step 2.11.4.3
Multiply 4 by 6.
f′′(x)=24x4+6(x2(4⋅-1))+6(x2-1)2
Step 2.11.4.4
Multiply 4 by -1.
f′′(x)=24x4+6(x2⋅-4)+6(x2-1)2
Step 2.11.4.5
Move -4 to the left of x2.
f′′(x)=24x4+6(-4⋅x2)+6(x2-1)2
Step 2.11.4.6
Multiply -4 by 6.
f′′(x)=24x4-24x2+6(x2-1)2
f′′(x)=24x4-24x2+6(x2-1)2
Step 2.11.5
Simplify each term.
Step 2.11.5.1
Rewrite (x2-1)2 as (x2-1)(x2-1).
f′′(x)=24x4-24x2+6((x2-1)(x2-1))
Step 2.11.5.2
Expand (x2-1)(x2-1) using the FOIL Method.
Step 2.11.5.2.1
Apply the distributive property.
f′′(x)=24x4-24x2+6(x2(x2-1)-1(x2-1))
Step 2.11.5.2.2
Apply the distributive property.
f′′(x)=24x4-24x2+6(x2x2+x2⋅-1-1(x2-1))
Step 2.11.5.2.3
Apply the distributive property.
f′′(x)=24x4-24x2+6(x2x2+x2⋅-1-1x2-1⋅-1)
f′′(x)=24x4-24x2+6(x2x2+x2⋅-1-1x2-1⋅-1)
Step 2.11.5.3
Simplify and combine like terms.
Step 2.11.5.3.1
Simplify each term.
Step 2.11.5.3.1.1
Multiply x2 by x2 by adding the exponents.
Step 2.11.5.3.1.1.1
Use the power rule aman=am+n to combine exponents.
f′′(x)=24x4-24x2+6(x2+2+x2⋅-1-1x2-1⋅-1)
Step 2.11.5.3.1.1.2
Add 2 and 2.
f′′(x)=24x4-24x2+6(x4+x2⋅-1-1x2-1⋅-1)
f′′(x)=24x4-24x2+6(x4+x2⋅-1-1x2-1⋅-1)
Step 2.11.5.3.1.2
Move -1 to the left of x2.
f′′(x)=24x4-24x2+6(x4-1⋅x2-1x2-1⋅-1)
Step 2.11.5.3.1.3
Rewrite -1x2 as -x2.
f′′(x)=24x4-24x2+6(x4-x2-1x2-1⋅-1)
Step 2.11.5.3.1.4
Rewrite -1x2 as -x2.
f′′(x)=24x4-24x2+6(x4-x2-x2-1⋅-1)
Step 2.11.5.3.1.5
Multiply -1 by -1.
f′′(x)=24x4-24x2+6(x4-x2-x2+1)
f′′(x)=24x4-24x2+6(x4-x2-x2+1)
Step 2.11.5.3.2
Subtract x2 from -x2.
f′′(x)=24x4-24x2+6(x4-2x2+1)
f′′(x)=24x4-24x2+6(x4-2x2+1)
Step 2.11.5.4
Apply the distributive property.
f′′(x)=24x4-24x2+6x4+6(-2x2)+6⋅1
Step 2.11.5.5
Simplify.
Step 2.11.5.5.1
Multiply -2 by 6.
f′′(x)=24x4-24x2+6x4-12x2+6⋅1
Step 2.11.5.5.2
Multiply 6 by 1.
f′′(x)=24x4-24x2+6x4-12x2+6
f′′(x)=24x4-24x2+6x4-12x2+6
f′′(x)=24x4-24x2+6x4-12x2+6
Step 2.11.6
Add 24x4 and 6x4.
f′′(x)=30x4-24x2-12x2+6
Step 2.11.7
Subtract 12x2 from -24x2.
f′′(x)=30x4-36x2+6
f′′(x)=30x4-36x2+6
f′′(x)=30x4-36x2+6
Step 3
To find the local maximum and minimum values of the function, set the derivative equal to 0 and solve.
6x(x2-1)2=0
Step 4
Step 4.1
Find the first derivative.
Step 4.1.1
Differentiate using the chain rule, which states that ddx[f(g(x))] is f′(g(x))g′(x) where f(x)=x3 and g(x)=x2-1.
Step 4.1.1.1
To apply the Chain Rule, set u as x2-1.
ddu[u3]ddx[x2-1]
Step 4.1.1.2
Differentiate using the Power Rule which states that ddu[un] is nun-1 where n=3.
3u2ddx[x2-1]
Step 4.1.1.3
Replace all occurrences of u with x2-1.
3(x2-1)2ddx[x2-1]
3(x2-1)2ddx[x2-1]
Step 4.1.2
Differentiate.
Step 4.1.2.1
By the Sum Rule, the derivative of x2-1 with respect to x is ddx[x2]+ddx[-1].
3(x2-1)2(ddx[x2]+ddx[-1])
Step 4.1.2.2
Differentiate using the Power Rule which states that ddx[xn] is nxn-1 where n=2.
3(x2-1)2(2x+ddx[-1])
Step 4.1.2.3
Since -1 is constant with respect to x, the derivative of -1 with respect to x is 0.
3(x2-1)2(2x+0)
Step 4.1.2.4
Simplify the expression.
Step 4.1.2.4.1
Add 2x and 0.
3(x2-1)2(2x)
Step 4.1.2.4.2
Multiply 2 by 3.
6(x2-1)2x
Step 4.1.2.4.3
Reorder the factors of 6(x2-1)2x.
f′(x)=6x(x2-1)2
f′(x)=6x(x2-1)2
f′(x)=6x(x2-1)2
f′(x)=6x(x2-1)2
Step 4.2
The first derivative of f(x) with respect to x is 6x(x2-1)2.
6x(x2-1)2
6x(x2-1)2
Step 5
Step 5.1
Set the first derivative equal to 0.
6x(x2-1)2=0
Step 5.2
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
(x2-1)2=0
Step 5.3
Set x equal to 0.
x=0
Step 5.4
Set (x2-1)2 equal to 0 and solve for x.
Step 5.4.1
Set (x2-1)2 equal to 0.
(x2-1)2=0
Step 5.4.2
Solve (x2-1)2=0 for x.
Step 5.4.2.1
Factor the left side of the equation.
Step 5.4.2.1.1
Rewrite 1 as 12.
(x2-12)2=0
Step 5.4.2.1.2
Since both terms are perfect squares, factor using the difference of squares formula, a2-b2=(a+b)(a-b) where a=x and b=1.
((x+1)(x-1))2=0
Step 5.4.2.1.3
Apply the product rule to (x+1)(x-1).
(x+1)2(x-1)2=0
(x+1)2(x-1)2=0
Step 5.4.2.2
If any individual factor on the left side of the equation is equal to 0, the entire expression will be equal to 0.
(x+1)2=0
(x-1)2=0
Step 5.4.2.3
Set (x+1)2 equal to 0 and solve for x.
Step 5.4.2.3.1
Set (x+1)2 equal to 0.
(x+1)2=0
Step 5.4.2.3.2
Solve (x+1)2=0 for x.
Step 5.4.2.3.2.1
Set the x+1 equal to 0.
x+1=0
Step 5.4.2.3.2.2
Subtract 1 from both sides of the equation.
x=-1
x=-1
x=-1
Step 5.4.2.4
Set (x-1)2 equal to 0 and solve for x.
Step 5.4.2.4.1
Set (x-1)2 equal to 0.
(x-1)2=0
Step 5.4.2.4.2
Solve (x-1)2=0 for x.
Step 5.4.2.4.2.1
Set the x-1 equal to 0.
x-1=0
Step 5.4.2.4.2.2
Add 1 to both sides of the equation.
x=1
x=1
x=1
Step 5.4.2.5
The final solution is all the values that make (x+1)2(x-1)2=0 true.
x=-1,1
x=-1,1
x=-1,1
Step 5.5
The final solution is all the values that make 6x(x2-1)2=0 true.
x=0,-1,1
x=0,-1,1
Step 6
Step 6.1
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 7
Critical points to evaluate.
x=0,-1,1
Step 8
Evaluate the second derivative at x=0. If the second derivative is positive, then this is a local minimum. If it is negative, then this is a local maximum.
30(0)4-36(0)2+6
Step 9
Step 9.1
Simplify each term.
Step 9.1.1
Raising 0 to any positive power yields 0.
30⋅0-36(0)2+6
Step 9.1.2
Multiply 30 by 0.
0-36(0)2+6
Step 9.1.3
Raising 0 to any positive power yields 0.
0-36⋅0+6
Step 9.1.4
Multiply -36 by 0.
0+0+6
0+0+6
Step 9.2
Simplify by adding numbers.
Step 9.2.1
Add 0 and 0.
0+6
Step 9.2.2
Add 0 and 6.
6
6
6
Step 10
x=0 is a local minimum because the value of the second derivative is positive. This is referred to as the second derivative test.
x=0 is a local minimum
Step 11
Step 11.1
Replace the variable x with 0 in the expression.
f(0)=((0)2-1)3
Step 11.2
Simplify the result.
Step 11.2.1
Raising 0 to any positive power yields 0.
f(0)=(0-1)3
Step 11.2.2
Subtract 1 from 0.
f(0)=(-1)3
Step 11.2.3
Raise -1 to the power of 3.
f(0)=-1
Step 11.2.4
The final answer is -1.
y=-1
y=-1
y=-1
Step 12
Evaluate the second derivative at x=-1. If the second derivative is positive, then this is a local minimum. If it is negative, then this is a local maximum.
30(-1)4-36(-1)2+6
Step 13
Step 13.1
Simplify each term.
Step 13.1.1
Raise -1 to the power of 4.
30⋅1-36(-1)2+6
Step 13.1.2
Multiply 30 by 1.
30-36(-1)2+6
Step 13.1.3
Raise -1 to the power of 2.
30-36⋅1+6
Step 13.1.4
Multiply -36 by 1.
30-36+6
30-36+6
Step 13.2
Simplify by adding and subtracting.
Step 13.2.1
Subtract 36 from 30.
-6+6
Step 13.2.2
Add -6 and 6.
0
0
0
Step 14
Step 14.1
Split (-∞,∞) into separate intervals around the x values that make the first derivative 0 or undefined.
(-∞,-1)∪(-1,0)∪(0,1)∪(1,∞)
Step 14.2
Substitute any number, such as -4, from the interval (-∞,-1) in the first derivative 6x(x2-1)2 to check if the result is negative or positive.
Step 14.2.1
Replace the variable x with -4 in the expression.
f′(-4)=6(-4)((-4)2-1)2
Step 14.2.2
Simplify the result.
Step 14.2.2.1
Multiply 6 by -4.
f′(-4)=-24((-4)2-1)2
Step 14.2.2.2
Raise -4 to the power of 2.
f′(-4)=-24(16-1)2
Step 14.2.2.3
Subtract 1 from 16.
f′(-4)=-24⋅152
Step 14.2.2.4
Raise 15 to the power of 2.
f′(-4)=-24⋅225
Step 14.2.2.5
Multiply -24 by 225.
f′(-4)=-5400
Step 14.2.2.6
The final answer is -5400.
-5400
-5400
-5400
Step 14.3
Substitute any number, such as -0.5, from the interval (-1,0) in the first derivative 6x(x2-1)2 to check if the result is negative or positive.
Step 14.3.1
Replace the variable x with -0.5 in the expression.
f′(-0.5)=6(-0.5)((-0.5)2-1)2
Step 14.3.2
Simplify the result.
Step 14.3.2.1
Multiply 6 by -0.5.
f′(-0.5)=-3((-0.5)2-1)2
Step 14.3.2.2
Raise -0.5 to the power of 2.
f′(-0.5)=-3(0.25-1)2
Step 14.3.2.3
Subtract 1 from 0.25.
f′(-0.5)=-3(-0.75)2
Step 14.3.2.4
Raise -0.75 to the power of 2.
f′(-0.5)=-3⋅0.5625
Step 14.3.2.5
Multiply -3 by 0.5625.
f′(-0.5)=-1.6875
Step 14.3.2.6
The final answer is -1.6875.
-1.6875
-1.6875
-1.6875
Step 14.4
Substitute any number, such as 0.5, from the interval (0,1) in the first derivative 6x(x2-1)2 to check if the result is negative or positive.
Step 14.4.1
Replace the variable x with 0.5 in the expression.
f′(0.5)=6(0.5)((0.5)2-1)2
Step 14.4.2
Simplify the result.
Step 14.4.2.1
Multiply 6 by 0.5.
f′(0.5)=3((0.5)2-1)2
Step 14.4.2.2
Raise 0.5 to the power of 2.
f′(0.5)=3(0.25-1)2
Step 14.4.2.3
Subtract 1 from 0.25.
f′(0.5)=3(-0.75)2
Step 14.4.2.4
Raise -0.75 to the power of 2.
f′(0.5)=3⋅0.5625
Step 14.4.2.5
Multiply 3 by 0.5625.
f′(0.5)=1.6875
Step 14.4.2.6
The final answer is 1.6875.
1.6875
1.6875
1.6875
Step 14.5
Substitute any number, such as 4, from the interval (1,∞) in the first derivative 6x(x2-1)2 to check if the result is negative or positive.
Step 14.5.1
Replace the variable x with 4 in the expression.
f′(4)=6(4)((4)2-1)2
Step 14.5.2
Simplify the result.
Step 14.5.2.1
Multiply 6 by 4.
f′(4)=24((4)2-1)2
Step 14.5.2.2
Raise 4 to the power of 2.
f′(4)=24(16-1)2
Step 14.5.2.3
Subtract 1 from 16.
f′(4)=24⋅152
Step 14.5.2.4
Raise 15 to the power of 2.
f′(4)=24⋅225
Step 14.5.2.5
Multiply 24 by 225.
f′(4)=5400
Step 14.5.2.6
The final answer is 5400.
5400
5400
5400
Step 14.6
Since the first derivative did not change signs around x=-1, this is not a local maximum or minimum.
Not a local maximum or minimum
Step 14.7
Since the first derivative changed signs from negative to positive around x=0, then x=0 is a local minimum.
x=0 is a local minimum
Step 14.8
Since the first derivative did not change signs around x=1, this is not a local maximum or minimum.
Not a local maximum or minimum
Step 14.9
These are the local extrema for f(x)=(x2-1)3.
x=0 is a local minimum
x=0 is a local minimum
Step 15