Which statement illustrates why cosine is an even function? cos(pie/4) = -cos(5pie/4)
cos(pie/4) = -cos(4pie/4) cos(-pie/4) = cos(pie/4)
cos(-7pie/6) = cos(5pie/4)

2men and 7 boys can do a piece of working 4 days. it is done by 4 men and 4 boys in 3 days how long would it take for 1man or one boy to do it alone

If the graphs of the linear equations in a system are parallel, what does that mean about the possible solution(s) of the system? a. there are infinitely many solutions. b. there is no solution. c. there is exactly one solution. d. the lines in a system cannot be parallel.

The figures below are made out of circles, semicircles, quarter circles, and a square. find the area and the perimeter of each figure and give your answers as a completely simplified exact value in terms of π (no approximations).