Write the area of the shaded region in terms of theta write

Question

In a geometric argument (see figure) was used to prove the following.

limit_θ→0 sin(θ)/θ= 1

a. Write the area of ΔABD in terms of θ.

b. Write the area of the shaded region in terms of θ.

c. Write the ratio R of the area of ΔABD to that of the shaded region.

d. Find the following limit.

limit_θ→0 R.