Use the attached figure to guide yourself through the explanation. In the figure:

.
We know that:

Also remmeber that the area of a triangle is:

The hegiht is shown in the figure in red, the base is just the b side.
Using the angle C the area of the triangle is:

Now taking the derivative of the area 2A with respect to t we have:

Replacing with the right values:

yields:
Answer:
(a) is 4*C and (B) is 16*C
The opposite of 3.5 is -3.5
Answer:

Step-by-step explanation:
By the theorem of intern angles of a triangle, we know that the sum of all intern angles of a triangle must be 180°, therefore:
*There are two equal angles because there are two equal sides

Now, applying the law of sines, we can find side a. The law of sines is represented by the following equation:

Hence, if b=100, alpha=40° and betha=70°, solve for a: