Prove sinxsin2x+cosxcos2x=cosx

How many lines of reflection symmetry does a trapezoid have

What is 3/8 because it's for my homework but it's really hard

Wave erosion causes a coastline to recede at a rate of 3.5 centimeters each year. After 9.25 years, how many centimeters will the coastline have receded?

A dresser in the shape of a rectangular prism measures 2 feet by 2 feet by 6 feet. What is the area?

5a - {3b - 5[a - (b + - 4a) ]}

the sum of the digits of a two-digit number is 9. when the digits are reversed, the new number is 9 more than the original number. find the original number. check your answer.

Prove that if a, b and c are odd integers such that a + b + c = 0, then abc < 0. (you are permitted to use well-known properties of integers here.) be sure to show all work.

The cost of one pound of peanuts is 60% of the cost of one pound of cashews. If one pound of cashews costs $2, what is the cost of one pound of peanuts? What is the total cost of two pounds of peanuts and one pound of cashews?

Whats the fuction that represents a geometric sequence

Emily is 50 years old. Colin is 18 years older than Emily. Dan is 6 years younger than Emily. What is the total of their combined ages?