Median of the Weibull Distribution

The Weibull distribution with shape $k > 0$ and scale $\lambda > 0$ has CDF $$F(x) = 1 - e^{-(x/\lambda)^k}, \quad x \geq 0.$$

(a) Derive a closed-form expression for the median of this distribution.

(b) Compute the median when $k = 2$ and $\lambda = 3$.