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- Mar 17th 2010, 04:54 PM #1

- Joined
- Nov 2009
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- 28

## No one knows how to do this question.?

Q19.A student models the evening lighting-up time by the equation L = 6.125 - 2.25cos(πt/6) where the time, L hours pm, is always in GMT ( Greenwich Mean Time) and t is in months, starting in mid-December. The model assumes that all months are equally long.

a)Calculate the value of L for mid-January and for mid-May

b)Find, by solving an appropriate equation, the two months in the year when the lighting up time will be 5pm (GMT).

c)Write down an equation for L if t were to be in months starting in mid-March.

- Mar 17th 2010, 05:24 PM #2