2. Substitute into the equation . So your other co-ordinate is .

3. The normal to a curve at a given pointPis the straight line perpendicular to the tangent atPand passing throughP. If the tangent has gradient , the gradient of the normal is .

In your example, the normal to the curve at is ; hence at . You should be able to findafrom here. Once you’ve founda, substitute into to find they-coordinate, which isb.