# Using the solve function for a more complex variable

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Noel Loh on 17 Jun 2020
Edited: Noel Loh on 23 Jun 2020
Hello,
the equations are as follows
i am trying to find cos2 (noted by c2) and sin2 (noted by s2), this is very simple if i did it via hand, but i am trying to solve this using matlab coding and i require some help as i cant seem to get the right answer using the solve function.
solution:

#### 1 Comment

darova on 18 Jun 2020

Devineni Aslesha on 23 Jun 2020
Hi Noel,
Use the solve function to find the solution for the above equations as shown below.
syms x y z s1 s2 c1 c2
eqn1 = x + s1*c2 == 0;
eqn2 = y - s1*s2 == 0;
eqn3 = z - c1 == 0;
eqns = [eqn1 eqn2 eqn3];
sol = solve(eqns,[c2 s2 z]);
Here, sol.c2, sol.s2 and sol.z are the required solutions

Noel Loh on 23 Jun 2020
thank you so much! that worked perfectly as i wanted it to go
madhan ravi on 23 Jun 2020
Noel next time please show some efforts and don’t expect others to write the code for you.
Noel Loh on 23 Jun 2020
thanks for your help mvp, i have spent weeks trying to solve it despite not being great at coding, finally solved it a few days ago, only to be recently reminded about the topic when an actual helpful person today helped give input on a possible solution, decided to thank the person's efforts without being rude, but also hear a supposingly mvp suddenly came in throwing an useless comment just to massage his tiny ego, but your comment helped i guess, good job.