# Homework Help: Really simple trig modeling question

1. May 3, 2005

### lektor

The average hours of sunlight can be modelled on

$$1.5\cos \frac {\pi(x-3)}{26}+6.5$$ where x is the number of weeks since the start of the year.

Ok. so it isn't really the calculation questions which are getting me, unfortunately it is just the reading of the model..

Here are the 2 questions i wasn't sure about

b) What is the greatest average number of sunlight per day expected in nelson and when.

c) in which week of the year would you expect the least.

Thanks in advance to thoose who help :)

2. May 4, 2005

### eax

How do you those nice writing anyway?

For B)
its when PI*(x - 3)/26 = 0 or 360 etc...
for C)
its when PI*(x-3)/26 = 180 or (180 + 360) etc ...

why?
cos 0 = 1 thus giving maximum
cos 180 = -1 thus giving minimum

Just solve for x
hope this helps!

3. May 4, 2005

### lektor

yeah man cheers, i figured it out just after i posted, i ignored the horizontal displacement :)

and as for the fancey writing :P

click my writing and then there should be something about a tutorial for it :0