What is the integral of (1+2x)^3 ?

The integral of (1+2x)^3 is 1/8 (1+2x)^4+C

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integral of (1+2x)^3

\int (1 + 2 x)^{3} d x

\frac{1}{8} (1 + 2 x)^{4} + C

Solution steps

\int (1 + 2 x)^{3} d x

Apply u-substitution

= \int \frac{u ^{3}}{2} d u

Take the constant out:

\int a \cdot f (x) d x = a \cdot \int f (x) d x

= \frac{1}{2} \cdot \int u^{3} d u

Apply the Power Rule

= \frac{1}{2} \cdot \frac{u ^{4}}{4}

Substitute back

u = 1 + 2 x

= \frac{1}{2} \cdot \frac{( 1 + 2 x ) ^{4}}{4}

Simplify

\frac{1}{2} \cdot \frac{( 1 + 2 x ) ^{4}}{4} : \frac{1}{8} (1 + 2 x)^{4}

= \frac{1}{8} (1 + 2 x)^{4}

Add a constant to the solution

= \frac{1}{8} (1 + 2 x)^{4} + C