Solve pls brainliest

Hello people, i have a math question that i need with, me, i will give the correct one brainiest, and for the other correct people, a and 5 stars.

Prove sin2a + cos2a - 1 / sin2a + cos2a + 1 = 1 - tana / 1 + cota

At the beginning of year 1, carlos invests $600 at an annual compound interest rate of 4%. he makes no deposits to or withdrawals from the account. which explicit formula can be used to find the account's balance at the beginning of year 5? what is, the balance?