Radical functions involve roots such as square roots or cube roots. The graph of y=√x starts at (0,0) and passes through (1,a), shifting horizontally and vertically based on h and k. Similarly, the graph of y=x1/3 passes through (0,0), (1,a) and (-1,-a), with an S-shape. To graph a square root function, sketch the parent graph y=√x, then apply transformations for h and k. Cube root graphs are drawn the same way but with both sides of the S-shape.