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 Posted: Mon Dec 08, 2008 5:15 pm
ok basically I'm trying to solve for B. The Book gave me. A=45, a=7 (square root) 2, b=7
This is a SAA which only has one solution.
So I do was the book says
SinA/a= SinB/b
The book then goes
SinB=bSinA/a
That I understand what I don't understand is that it then does this to me
7/7(squareroot of 2) (sin45)
So apprerently it is no longer in the numerator. It is multiplied by a fraction (sin 45) How the hell does this happen and why? Isn't 7 supposed to be multiplied by Sin45 then devided by 7 square root of 2? I'm confused a simple explenation would help me greatly.
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Posted: Wed Dec 10, 2008 8:51 am
I think you *do* understand it correctly... from what you wrote, the book is just being a bit cavalier about order of operations:
but first, notice that
x/y*z means x * 1/y * z (which also can be represented as (x/y)*z),
since order doesn't matter in multiplication (it's commutative), we can rearrange the terms... so
bSinA/a = b * SinA * 1/a which is the same thing as
b*1/a*SinA, which is the same as
(b/a)*SinA
So your answer is correct, and so is the book (assuming I read your post carefully enough).
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