Question

Use the diagram to derive the law of cosines. Which of the following statements is true?

a.b=ccosA
b.x=acosC
c.c=hcosA
d.(b)/(x)=(c)/(b)

Answer 1

The law of cosines states that in any triangle, the square of one side is equal to the sum of the squares of the other two sides minus twice the product of the lengths of those two sides multiplied by the cosine of the included angle.

Step-by-step explanation:

The law of cosines is derived from the right triangle in Figure 2.18. The law states that in any triangle, the square of one side is equal to the sum of the squares of the other two sides minus twice the product of the lengths of those two sides multiplied by the cosine of the included angle.

In equation form, this can be written as: c2 = a2 + b2 - 2ab cos(C).

So, the correct statement is: a. b = c cos(A).