Question

The desert temperature, H, oscillates daily between 38ºF at 6am and 78ºF at 6pm. Write a possible formula for H in terms of t, measured in hours from 6am. Use the form

H = A cos(Bt) + C

I have figured out that b is pi/12 and c is 58 but i can't find A even with plugging them in because i don't know the proccess.