Prove that tan theta -cot theta / sin theta - cis theta =tan 2 theta -cot2 theta

Ken earned $128 from his part-time job this summer. he spent 25% of his money on games. he is going to donate 1/6 of the remaining money to charity. how much money will the charity receive?

Sections of prefabricated wood are each 5 1/3 feet long. how long are 7 1/2 sections placed end to end?

Danny can read 4 pages in 12 minutes. how many pages can he read in 1 hour?