Consider the geometric series 64 + 96 + 144 + 216 + ... Find the common ratio r and the sum of the first 10 terms of this series. If necessary, round to the nearest thousandth.

7. if the value of x varies directly with the value of y, and x = 3 when y = 21. what is the valu y, and x = 3 when y = 21. what is the value of x when y = 105?

Astuntman jumping off a 20-m-high building is modeled by the equation h=20-5t^2, where t is the same in seconds. a high-speed camera is ready to film him between 15m and 10m above the ground. for which interval of time should the camera film him?

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).