Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
NCTM or The Math Forum.


Torsten
Posts:
1,684
Registered:
11/8/10


Re: 3 equation of cosine law
Posted:
Mar 28, 2013 3:44 AM


"DHAAH JOHARI" wrote in message <kiveni$nan$1@newscl01ah.mathworks.com>... > "Torsten" wrote in message <kip1uf$5ot$1@newscl01ah.mathworks.com>... > > "DHAAH JOHARI" wrote in message <kik48r$k5a$1@newscl01ah.mathworks.com>... > > > > I think you want to use "cosd" instead of "cos" in your equations. > > > > > > > > Best wishes > > > > Torsten. > > > > > > Thanks Torsten..thank you very much! > > > but I still didn't get the answers,.. > > > It said error..i don't know how to fix it > > > > > > syms xyz > > > solutions = solve('x^2 = y^2+233600966.64*y*cosd(z65.56) ',' x^2 = y^2+155600788.92*y*cosd(z59.53)','x^2 = y^2+97600624.82*y*cosd(z50.19)') > > > [solutions.x solutions.y solutions.z] > > > > I think cosd does not accept symbolic arguments. > > Convert 65.56°, 59.53° and 50.19° to radians and try again. > > And define > > syms x y z > > instead of > > syms xyz > > > > Best wishes > > Torsten. > > Thanks again Torsten.. > i have converting the 65.56°, 59.53° and 50.19° to radians and define syms x y z..but i still didn't get the answers.. > is it right if i wrote like this..so sorry to have bothered you > > syms x y z > solutions = solve('x^2 = y^2+233600966.64*y*cos(z1.14) ',' x^2 = y^2+155600788.92*y*cos(z1.04)','x^2 = y^2+97600624.82*y*cos(z0.88)') > [solutions.x solutions.y solutions.z]
What do you get if you execute syms x y z solutions = solve(x^2 == y^2+233600966.64*y*cos(z1.14), x^2 == y^2+155600788.92*y*cos(z1.04), x^2 == y^2+97600624.82*y*cos(z0.88)) [solutions.x solutions.y solutions.z] and why is this solution not the solution you expect ?
If I insert x=444.46, y=149.25 into the equation and solve each equation seperately for z, I _don't_ get the same zvalues (for the first equation, I get z=2.29, for the second 2.78 and for the third z=3.44) So I don't understand why you think that x=444.46, y=149.25 is a solution.
Best wishes Torsten.



