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2 equations, 2 unknowns 
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#1
Mar2007, 06:02 PM

P: 203

1. The problem statement, all variables and given/known data
I can't remember how to solve these equations like this one. I need to solve for each variable. I'm not sure I've ever known how to do this. 720 + Tab*cos(36.8699) + Taf*cos(20.556) 660 + Tab*sin(53.1301) + Taf*sin(69.444) I need to solve for both Tab and Taf. This is possible, right? 2. Relevant equations 3. The attempt at a solution Don't even know where to start...need help! Thanks, Brad 


#2
Mar2007, 06:10 PM

P: 560

These are not equations, there are no equal signs. Thus they cannot be solved. But, if they were to have equal signs, sin (53.1301) just represents a number right? If you 53.1301 is in degrees and not radians (very likely) then sin (53.1301)= [tex]0.8[/tex]
To solve two equations in two unkowns, there are a few ways. Perhaps the easiest is to solve for one variable in one of the equations in terms of the other equation and then plug that into the other equation. So lets say you have two equations in y and x such as: 3x+y=5 y+5x=2 You could solve the second one for y.. y=25x right? now plugging it into the first one you get 3x+25x=5 2x=3 x=2/3 Now just plug x=2/3 into the other equation and solve for y. Easy. 


#3
Mar2007, 06:44 PM

P: 203

Ok so is this right then....
Solving second equation for Tab Tab = =(Taf(.936)  660)/.8 Then insert back into equation 1.... 720  Taf(.936)  660 + Taf(.936) = 0 These are all equal to zero, forgot to add that in....and yes, they are degrees. If that is right, I can't get an answer to come out. 


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