Does anyone know number 9 i'm doing test corrections what's the answer ?

Ineed to know the answer to this algebra question.

Pepe and leo deposits money into their savings account at the end of the month the table shows the account balances. if there pattern of savings continue and neither earns interest nor withdraw any of the money , how will the balance compare after a very long time ?

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