A company's sales are seasonal with the peak in mid-December and the lowest point in mid-June. The company makes $100,000 in sales in December, and only $20,000 in June.

(a) Find a trigonometric function, s = f(t), representing sales at time t months after mid-January

i know the period is 12 and the midline is 60,000 and the amp is 40,000 but i don't know where to go from there

Question

A company's sales are seasonal with the peak in mid-December and the lowest point in mid-June. The company makes $100,000 in sales in December, and only $20,000 in June.

(a) Find a trigonometric function, s = f(t), representing sales at time t months after mid-January

i know the period is 12 and the midline is 60,000 and the amp is 40,000 but i don't know where to go from there

anonymous · Answer

$$60000+40000\cos(\pi/6t)$$ that is what i have so far but I know that is wrong

baru · Answer

$60000+40000cos (\frac{\pi }{6}t -\phi) $

baru · Answer

find $\phi$ by plugging in t=6, f(t)=20000