The slope of the tangent at the point $(h, h)$ of the circle $x^2 + y^2 = a^2$ is

The slope of the tangent to the circle $x^2 + y^2 = a^2$ at the point $(h, k)$ is:

If $\Delta$ is the area of the triangle formed by the positive $x$-axis and the normal and tangent to the circle $x^2+y^2=4$ at $(1, \sqrt{3})$,then $\Delta$ is equal to

The line $lx + my + n = 0$ will be a tangent to the circle $x^2 + y^2 = a^2$ if

The tangent to the circle $x^2 + y^2 = 10$ at the point $(3, 1)$ touches the circle $x^2 + y^2 - 2\sqrt{10}x - 20y + k = 0$. Find the value of $k$.

If the line $y = mx + c$ is a tangent to the circle $x^2 + y^2 = a^2$,then the point of contact is