I have a problem and I am stuck to one question:

**The area of a triangle is given by the formula: A=1/2*b*c*sin(θ )**

At time to, we have bo=10 inches, co=20inches, θo=pi/3

At time to, we have bo=10 inches, co=20inches, θo=pi/3

a) Find the area of the triangle at to

**I found 50*sqrt(3)**

b- find the rate of change of the area with respect to b at to.

**I found 5*sqrt(3).**

c) Find the rate of change of the area with respect with θ at to.

**I found 50.**

d) Using the rate found in part c) , calculate (by differentials) the approximate change in area if angle theta is increased by one degree.

**I need help for this question. I do not know what to do here.**

Thank you for your help