# Partial derivations

1. Oct 9, 2005

Hi,
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

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.

2. Oct 9, 2005

### lightgrav

I'm guessing that b is the hypotenuse and c is the leg