Question

If A + B + C = $\pi ,$ the maximum value of cos A + cos B + cos C can have is --

• A. 1
• B. $\frac{3}{2}$
• C. 2
• D. 3

Answer 1

The correct option is B $\frac{3}{2}$

If A + B + C =$\pi ,$ then the maximum value cos A + cos B + cos C can have is = $\frac{3}{2}.$
The proof of this beyond the scope of this chapter.