Wind Load Formula

[cuad]

I'm not sure where to post this, so please excuse me if this is misplaced. I need help understanding how the terms are grouped in this formula for A = pressure normal to the roof. If any of you are familiar with this formula or can link me to a source containing better expressed formulas like this one I'd appreciate your help. I'm posting a screen shot of the formula from a textbook I'm looking at. It looks something like:
A = Fsinx^1.84cos-1

Apparently it's a formula belonging to someone called Charles Hutton and it looks something more like Pn= P(sinx)^(1.842cosx-1) I just want to double check whether the exponent is really (1.842cosx-1) and not something like 1.842cos(x-1).

http://i33.tinypic.com/13z6fqt.jpg

[FredGarvin]

I have never heard of it, but there is another source I found that references it as well (it even talks about the experimental basis for the equation):

When attempting to bring the velocity up to 20
ft. per sec. or 13.6 miles per hour, the thread carrying
the weight broke. These experiments are recorded under
dates of July 24, 25, 31 and Aug. 11. The results ob-
tained were tabulated and the well known formula
Pn = P (sitfx) l -**co*x-i

http://www.archive.org/stream/sixmonographsonw00flemrich/sixmonographsonw00flemrich_djvu.txt

[nvn]

cuad: First, from other sources, we know your attached image in post 1 is missing parentheses around sin theta. Secondly, because addition and subtraction have a low precedence of arithmetic operations, unlike multiplication, we know addition and subtraction expressions can be passed to a function only if the addition or subtraction expression argument is enclosed in parentheses, such as cos(x - 1). Therefore, we know the formula is Pn = P*(sin theta)^[(1.842*cos theta) - 1].

[cuad]

Hi everyone. Thank you guys for clarifying that for me.