Question

The law of cosines is a2+b2-2abcosC=c2 find the value of 2abcosC

Answer 1

2ab * cos (C)= 7

hope this helps you

Answer 2

Isolating 2abCos(c) on one side of the equation and using the given values of a, b and c we can find the answer to this question as shown below:


`a^(2) + b^(2) -2ab*cos(C)=c^(2) \\ \\ 2ab *cos(C)= a^(2) + b^(2) - c^(2) \\ \\ 2ab *cos(C)=2^(2) + 2^(2)- 1^(2) \\ \\ 2ab*cos(C) = 7`