4. What is the main difference between a refracting telescope and a reflecting telescope? A refracting telescope uses a concave lens to collect light; a reflecting telescope uses a concave mirror to collect light.
A refracting telescope uses a convex lens to collect light; a reflecting telescope uses a concave mirror to collect light.
A refracting telescope uses a convex lens to collect light; a reflecting telescope uses a convex mirror to collect light.

we have been given a quadratic function and we need to restrict the domain such that it becomes a one to one function.

we know that vertex of this quadratic function occurs at (5,2).

further, we know that range of this function is .

if we restrict the domain of this function to either or , it will become one to one function.

let us know find its inverse.

upon interchanging x and y, we get:

let us now solve this function for y.

hence, the inverse function would be if we restrict the domain of original function to and the inverse function would be if we restrict the domain to .

54 degrees incident angle = reflected angle

angle is from normal turned to line of ray