To write 1/2 as a radical expression, you can express it as the square root of 1 divided by the square root of 2. This can be simplified further by rationalizing the denominator.
1/2 = √1/√2
= √1/√2 * √2/√2 (multiplying by √2/√2 to rationalize the denominator)
= √2 / 2
Therefore, 1/2 can be written as √2 / 2 in radical form.