Find the exact values of sin(2θ), cos(2θ), and tan(2θ) given sec(θ) = − 15/9 and θ is in the interval [pi/2, pi]

i have cos(2theta) which is -7/25 but i miscalculated the other values.

The table above shows approximate conversions from gallons to liters. what is the value of x?

Lin is writing an equation to model the proportional relationship between y, the total cost in dollars of downloading videos from a website, and x, the number of videos downloaded. she knows that the total cost to download 3 videos was $12. her work to find the equation is shown below. joylin’s work step 1 k= 3/12= 0.25 step 2 y= 0.25x where did joylin make her first error?

2x minus y equals 6, x plus y equals negative 3