Question

Write the expression as either the sine, cosine, or tangent of a single angle.

cosine of pi divided by three times cosine of pi divided by five plus sine of pi divided by three times sine of pi divided by five.

Answer 1

@mathmath333 please please please help?

Answer 2

can u write the equation

Answer 3

\[\cos (\pi/3) * \cos (\pi/5) + \sin (\pi/3) * \sin(\pi/5)\]

Answer 4

u can use the formula here

\(\large\tt \color{black}{cos(A-B)=cosA\times cosB+sinA\times sinB}\)

\(\large\tt \color{black}{cos(\frac{\pi}{3})\times cos(\frac{\pi}{5})+sin(\frac{\pi}{3})\times sin(\frac{\pi}{5})}\)

\(\large\tt \color{black}{=cos(\frac{\pi}{3}-\frac{\pi}{5})}\)

\(\large\tt \color{black}{=cos(\frac{5\pi-3\pi}{15})}\)

\(\large\tt \color{black}{=cos(\frac{2\pi}{15})}\)

Answer 5

Thank you. I had that answer. And the math. I just thought I was wrong. I appreciate it.