Express the illuminance on the floor as a composite function of t for 0 < t < 8.

The formula for illuminance is given by

E = I / d^2

This formula only holds true for one-dimensional illuminance

The problem asks for the illuminance across the floor. We need to use two variables, x and y.

From Pythagorean Theorem

d^2 = x^2 + y^2

and from Trigonometry

x = d cos t

y = d sin t

The function for the illuminance can be represented by the composite function

E = I cos² t / x²

and

E = I sin² t / y²

The boundary of these functions is:

0 < t < 8

So, the value of t must be in radians and not in degrees