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I want to solve the equations below for Va and Ha given Vb and Hb. I have seen mathcad solve for coefficents of linear systems of equations but can mathcad solve these leaving the trig functions?
Vb=atan(tand(Va)/cos(Ha)); Va and Ha in degrees
Hb= asin(cos(VA)*sin(Ha)); Va and Ha in degrees
If you mean solve them numerically, yes. Look up solve blocks in the help.
By the way,
These are nonlinear equations, so look for that in help also. I took a quick stab at solving for one angle and substituting into the other equation and using solve, and back substitute, and it can find a symbolic solutionS that way, and its ugly. Makes me want to question the equations first. I may have made a mistake, but I am pretty sure its really ugly.
wayne wrote:
By the way,
.... I took a quick stab at solving for one angle and substituting into the other equation and using solve, and back substitute, and it can find a symbolic solutionS that way, and its ugly. Makes me want to question the equations first. I may have made a mistake, but I am pretty sure its really ugly.
Ugly it is! Mathcad needs a lot of help on this one. See attached.
Alan
Thanks for the help.
I think I got the solve block code working see the attached file.
Vb Hb Va Ha
5.02 4.98 5 5
7.05 44.78 5 45
27.24 41.64 20 45
I agree that the equations got ugly. They came out of a spec and I tryied to hand solve them but git lost in the process. I reviewed the file you sent me and the second equation should have been sin(Hb)=cos(Va)Sin(Ha) (multiplication)
I will see If I can use your format and modify it.
Thanks for your help
The equations are now less ugly, but I still wouldn't want to do it by hand.
Thanks for the help. I still need to review the file in more detail before I even start to ask more questions.
Note to self: read the question more carefully! Just for completeness, I attach my version with the (hopefully!) correct equations.
Alan
Note to self: read the question more carefully! Just for completeness,
Actually, I think the first post was edited. IIRC, the second equation originally had division, not multiplication.
Thanks guys for all the help. I will review all the files.
As to the question on the first post to my knowledge it is unedited. I know I didn't change anything. I am sorry there was some sort of misunderstanding though. Once again thanks for all the help it definity saved me a whole bunch of paper and time.
I guess I need to read the question more carefully too then. The first time I typed everything into Mathcad I know I also had division in both equations, because I got the same answer Alan did
I took a similar approach, substituting names for cos(ha) and cos(va) and putting all of the ha-va dependence in terms of these, then solving. However, after seeing the results others got, I just solved on paper and came up woth a reasonably simple result (attached). I didn't bother typing the whole thing (not really that long on paper), but I did check the result. Both my solution and Alan's HaVa2 solutions(either the 0 or 1 subscript) check with the original equations, so they must be equivalent - but not so obvious by just looking.
Lou
Yes, solve blocks are amazing!
One thing to be wary about though: solve blocks solve the equations iteratively and thus depend on the initial guess you give. Just check your answers to see if they make sense.