Simplify the following radical expression

sqrt(a^18 b^4)

To simplify the radical expression sqrt(a^18 b^4), we can break down the terms inside the square root.

sqrt(a^18 b^4) = sqrt(a^18) * sqrt(b^4)

Taking the square root of a^18, we can rewrite it as a^(18/2) = a^9.

Similarly, taking the square root of b^4, we can rewrite it as b^(4/2) = b^2.

Therefore, sqrt(a^18 b^4) simplifies to:

sqrt(a^18 b^4) = sqrt(a^9) * sqrt(b^2) = a^9 * b^2