Giải phương trình: cot^22x -4cot2x+3=0

5500 dollars is placed in an account with an annual interest rate of 6.5%. to the nearest tenth of a year, how long will it take for the account value to reach 19700 dollars?

Aman is 6 feet 3 inches tall. the top of his shadow touches a fire hydrant that is 13 feet 6 inches away. what is the angle of elevation from the base of the fire hydrant to the top of the man's head?

What are the coordinates of the point that is 1/3 of the way from a to b? a (2,-3) b (2,6)