If the chord of contact of tangents from a point `P` to the parabola `y^2=4a x` touches the parabola `x^2=4b y ,` then find the locus of `Pdot`

Explanation

To solve the problem, we need to find the locus of the point \( P(h, k) \) from which tangents are drawn to the parabola \( y^2 = 4ax \) and that the chord of contact touches another parabola \( x^2 = 4by \).

### Step 1: Write the equation of the chord of contact
The equation of the chord of contact from the point \( P(h, k) \) to the parabola \( y^2 = 4ax \) is given by:
\[ yy_1 = 2a(x + x_1) \]
Substituting \( (h, k) \) for \( (x_1, y_1) \), we get:
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