Chord gradients approaching a tangent gradient

\(P(2,4)\) and \(Q(2+h,(2+h)^2)\), where \(h\ne0\), are points on the curve \(y=x^2\).

1. Show that the gradient of the chord \(PQ\) is \(4+h\).[2]
2. Find the gradient of \(PQ\) when \(h=0.1\) and when \(h=-0.01\). Explain what these values suggest about the gradient of the tangent to the curve at \(P\).[2]
3. Using your answer to (b), find the equation of the tangent at \(P\) and the point where it meets the \(x\)-axis. Hence, using the symmetry of the curve, write down the gradient of the tangent at \((-2,4)\), with a reason.[3]