Calculus Examples
y′=3x2 , y=x3-4+c , y(0)=5
Step 1
Step 1.1
Find y′.
Step 1.1.1
Differentiate both sides of the equation.
ddx(y)=ddx(x3-4+c)
Step 1.1.2
The derivative of y with respect to x is y′.
y′
Step 1.1.3
Differentiate the right side of the equation.
Step 1.1.3.1
By the Sum Rule, the derivative of x3-4+c with respect to x is ddx[x3]+ddx[-4]+ddx[c].
ddx[x3]+ddx[-4]+ddx[c]
Step 1.1.3.2
Differentiate using the Power Rule which states that ddx[xn] is nxn-1 where n=3.
3x2+ddx[-4]+ddx[c]
Step 1.1.3.3
Since -4 is constant with respect to x, the derivative of -4 with respect to x is 0.
3x2+0+ddx[c]
Step 1.1.3.4
Since c is constant with respect to x, the derivative of c with respect to x is 0.
3x2+0+0
Step 1.1.3.5
Combine terms.
Step 1.1.3.5.1
Add 3x2 and 0.
3x2+0
Step 1.1.3.5.2
Add 3x2 and 0.
3x2
3x2
3x2
Step 1.1.4
Reform the equation by setting the left side equal to the right side.
y′=3x2
y′=3x2
Step 1.2
Substitute into the given differential equation.
3x2=3x2
Step 1.3
The given solution satisfies the given differential equation.
y=x3-4+c is a solution to y′=3x2
y=x3-4+c is a solution to y′=3x2
Step 2
Substitute in the initial condition.
5=03-4+c
Step 3
Step 3.1
Rewrite the equation as 03-4+c=5.
03-4+c=5
Step 3.2
Simplify 03-4+c.
Step 3.2.1
Raising 0 to any positive power yields 0.
0-4+c=5
Step 3.2.2
Subtract 4 from 0.
-4+c=5
-4+c=5
Step 3.3
Move all terms not containing c to the right side of the equation.
Step 3.3.1
Add 4 to both sides of the equation.
c=5+4
Step 3.3.2
Add 5 and 4.
c=9
c=9
c=9