What is a double angle identity to find the exact value of cos? Group of answer choices

cos⁡(2a)=〖cos〗^2⁡(a)+〖sin〗^2⁡(a)

cos⁡(2a)=〖cos〗^2⁡(a)

cos⁡(2a)=2 〖cos〗^2⁡(a)-1

cos⁡(2a)=〖2cos〗^2⁡(a)-2 〖sin〗^2⁡(a)

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?