Four times as much as the sum of 1/5 and 2/3

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

Three baby penguins and their father were sitting on an iceberg 0.50.50, point, 5 meters above the surface of the water. the father dove down 4.74.74, point, 7 meters from the iceberg into the water to catch dinner for his kids. what is the father penguin's position relative to the surface of the water?

What does independent variable and dependent variable mean in math?