A trough is filled with water

Sketch one cycle if the cosine function y=2cos2theta

The two square pyramids are similar. find the total volume of both pyramids if the ratio of their surface areas is 9/16

Aparticular telephone number is used to receive both voice calls and fax messages. suppose that 25% of the incoming calls involve fax messages, and consider a sample of 25 incoming calls. (a) what is the expected number of calls among the 25 that involve a fax message?