SecA-tanA/secA+tanA=cos^2A/(1+sin^2 A)​ could somebody prove this pls

Mr. and mrs. wallace have decided to buy a car for $21,600. they finance $15,000 of it with a 5-year auto loan at 2.9% arp. what will be their monthly payment be? a. $268.20 b. $268.86 c. $269.54 d. $387.16 i need !

In an equilateral triangle, each angle is represented by 5y+3. what is the value of y? a. 9.7 b. 10.8 c. 11.4 d. 7.2

Why is it so easy to buy on impulse and overspend with a credit card? what could you do to counteract this tendency?