Solving multiple equations using Matlab

avi2112ben

Hi all,
I am quite a newbie using Matlab.. I am trying to get Matlab to solve a set of 12 equations with 12 variables using the solve function. I have written something similar to this (I pasted the original at the end):

>>solve=('equa1','equa2',..,'equa12','var1',..,'var12')

Matlabs gives a Warning:Explicit solution could not be found

Would thanks any tips..
Avi


The line:
>> solve('D1^2=h2^2+m^2' , 'D2^2=C1^2+C2^2-2*C1*C2*cos(s1)' , 'L1+L2=C5' , 'sin(b1)=C3/L1*sin(s1+a1)' , 'cos(b3)=(C5^2+D1^2-D2^2)/(2*C5*D1)' , 'sin(b1)=C3/C2*sin(b2+a2)' , 'cos(s2)=(C1^2+h^2-H^2)/(2*C1*h)' , 'sin(b4)=C2/D2*sin(s1)' , 'sin(b5)=L1/D2*sin(b2)' ,'tan(b7)=m/h', 'cos(b6)=(D1^2+C4^2-L2^2)/(2*D1*C4)' , 's2+b4+b5+b6+b7=360', 's1', 's2', 'b1', 'b2', 'b3', 'b4', 'b5', 'b6', 'b7', 'L1', 'L2', 'D2')

edcentric

My head hurts trying to read the equasions. Are you sure that you have enough constraints? The warning sounds like you don't.
Does the system have a unique solution, or are there multiple solutions?

rebbo

Have you tried kluid??

anyway, why don't I see D1, h2, m ... in the declared varialbe list. Count the number of unknowns and number of equations ... you will know why its not working.

Rebbo

avi2112ben wrote:

>>solve=('equa1','equa2',..,'equa12','var1',..,'var12')

Matlabs gives a Warning:Explicit solution could not be found


The line:
>> solve('D1^2=h2^2+m^2' , 'D2^2=C1^2+C2^2-2*C1*C2*cos(s1)' , 'L1+L2=C5' , 'sin(b1)=C3/L1*sin(s1+a1)' , 'cos(b3)=(C5^2+D1^2-D2^2)/(2*C5*D1)' , 'sin(b1)=C3/C2*sin(b2+a2)' , 'cos(s2)=(C1^2+h^2-H^2)/(2*C1*h)' , 'sin(b4)=C2/D2*sin(s1)' , 'sin(b5)=L1/D2*sin(b2)' ,'tan(b7)=m/h', 'cos(b6)=(D1^2+C4^2-L2^2)/(2*D1*C4)' , 's2+b4+b5+b6+b7=360', 's1', 's2', 'b1', 'b2', 'b3', 'b4', 'b5', 'b6', 'b7', 'L1', 'L2', 'D2')

samira_8511

hi i have the same problem with 6 equations and 5 variabled, how did you solve your problem 2 years ago?;)

avi2112ben wrote:

Hi all,
I am quite a newbie using Matlab.. I am trying to get Matlab to solve a set of 12 equations with 12 variables using the solve function. I have written something similar to this (I pasted the original at the end):

>>solve=('equa1','equa2',..,'equa12','var1',..,'var12')

Matlabs gives a Warning:Explicit solution could not be found

Would thanks any tips..
Avi


The line:
>> solve('D1^2=h2^2+m^2' , 'D2^2=C1^2+C2^2-2*C1*C2*cos(s1)' , 'L1+L2=C5' , 'sin(b1)=C3/L1*sin(s1+a1)' , 'cos(b3)=(C5^2+D1^2-D2^2)/(2*C5*D1)' , 'sin(b1)=C3/C2*sin(b2+a2)' , 'cos(s2)=(C1^2+h^2-H^2)/(2*C1*h)' , 'sin(b4)=C2/D2*sin(s1)' , 'sin(b5)=L1/D2*sin(b2)' ,'tan(b7)=m/h', 'cos(b6)=(D1^2+C4^2-L2^2)/(2*D1*C4)' , 's2+b4+b5+b6+b7=360', 's1', 's2', 'b1', 'b2', 'b3', 'b4', 'b5', 'b6', 'b7', 'L1', 'L2', 'D2')