Prove, using a combinatorial (counting) argument, that c(2n, 2) = 2c(n, 2) + n 2

Carley bought a jacket that was discounted 10% off the original price. the expression below represents the discounted price in dollars, based on x, the original price of the jacket.

What is the point of inflection for the function f(x)=2cos4x on the interval (0, pi/2)

Tim knows the volume and base area of a wooden chest that is in the shape of a rectangular prism. if the volume is 524 cubic unit and the base area is 15 square unit, what is the height of the chest? 124 unit 1124 units 112 unit 1112 units