Hi Jaden,
For using the 'solve' function, I recommend going through the the examples in the function's documentation. The following is one relevant example that shows the use of 'solve' function to get real solutions:
For the condition that 't' needs to be positive, the following are the alternatives:
1. You can include the equation 't>0' in your system of equations as an input to the 'solve' function.
2. You can call the assume function before solving the equations as:
assume(t>0)
For more information, please refer to the following documentation for the 'assume' function:
3. You can solve for 't^2' instead of 't' and then square the resulting solution at the end. This method is explained in the following MATLAB Answers post:
https://www.mathworks.com/matlabcentral/answers/164468-how-to-make-sure-that-fsolve-gives-only-positive-values-as-the-solution
