Look at this set of ordered pairs:
(6, 4)
(9, 20)
(15, 15)
(12, 3)

Is this relation a function?

Which expression gives the area of the triangle shown below

The figures below are made out of circles, semicircles, quarter circles, and a square. find the area and the perimeter of each figure and give your answers as a completely simplified exact value in terms of π (no approximations).

Prove sin2a + cos2a - 1 / sin2a + cos2a + 1 = 1 - tana / 1 + cota