1. easy integral

the integral sign and then x^3 sqrt of x

i know the integral of x^3= x^4/4 +C
i know the integral of the sq rt of x= 2X^(3/2)/3 +C
but when i multiply these together im not getting 2x^(9/2)/9 +C as my answer
please show me where i am going wrong

2. Hello, vinson24!

You can't separate functions that way . . .

$\int x^3\sqrt{x}\,dx$

Note that: . $x^3\cdot\sqrt{x} \;=\;x^3\cdot x^{\frac{1}{2}} \;=\;x^{\frac{7}{2}}$

Now integrate: . $\int x^{\frac{7}{2}}\,dx$

3. thanks alot