C- Often times, if someone is using a coupon, they just want the lowest price and don't care what toothpaste is considered "the Best."
Y=Acos(p)+m, A=amplitude, p=period, m=midline, in this case:
A=1/2, p=360(t/12)=30t, m=(10-9)/2+9=9.5 so
h(t)=(1/2)cos(30t)+9.5
Are you asking what the answer is because you are not asking us anything. I would really like to help you out but I need to know what the question is first.
