What are the cycles per second in the simple harmonic motion described by d=8 cos (pi/2)t? what is the time per second, required per cycle?

If 1/√5+1/√5+1=p+q√r , find the values of p, q and r

65% of students in your school participate in at least one after school activity. if there are 980 students in you school, how many do not participate in an after school activity?

Segment an is an altitude of right δabc with a right angle at a. if ab = 2, squared 5 in and nc = 1 in, find bn, an, ac.