Question: RE: how to solve a matrix equation

Hello there, 

When I tried to use 'solve' command to solve an algebraic matrix equation, I got this error:

Would you please tell me the correct way to solve it?

eq6_3_sol := T__PhPh = solve(eq6_3_1, T__PhPh);
Error, invalid input: solve expects its 1st argument, eqs, to be of type {`and`, `not`, `or`, algebraic, relation(algebraic), ({list, set})({`and`, `not`, `or`, algebraic, relation(algebraic)})}, but received (Vector(3, {(1) = cos(omega__o*t), (2) = -cos(omega__o*t+(1/3)*Pi), (3) = -sin(omega__o*t+(1/6)*Pi)})) = T__PhPh . (Vector(3, {(1) = cos(omega__i*t), (2) = -cos(omega__i*t+(1/3)*Pi), (3) = -sin(omega__i*t+(1/6)*Pi)}))
 

The matrix equation I tried to solve is presented below:

(sorry for the duplication below, perhaps the Maple app which is supposed to display the content of the worksheet is not too happy with Microsoft Edge browser)

Download Q20210127.mw