# How to solve these equations?

I tried to solve these two equations by Solve function and Reduce, but it does not work. Mathematica shuts down! Can anyone help me, please?

eq1 = (1500 - 100/Sin[alp])/Sin[180 - alp - th2] == (1176.795 - 100/Tan[alp])/Sin[th2];
eq2 = 200 Cos[90 - alp - th2] - 500 Sin[alp] == 100;
Solve[{eq1,eq2},alp]

• Are you sure you meant Sin[180 - alp - th2] and not Sin[Pi - alp - th2] and same for Cos[90 - alp - th2]. If you want 90 to be degrees, need to use 90 Degree or better just use Pi/2 . – Nasser Oct 8 '17 at 18:20
• yes , I meant Pi instead of 180 – Ahmed kh Oct 8 '17 at 18:54

Try this and see if it gives you what you expect

eq1=(1500-100/Sin[alp])/Sin[Pi-alp-th2]==(1176.795-100/Tan[alp])/Sin[th2];
eq2=200 Cos[Pi/2-alp-th2]-500 Sin[alp]==100;
Solve[Rationalize@{eq1,eq2},{alp,th2},Reals]//N
`

• thanks its work , you can use Normal[%] /. {C[1] -> 0 , C[2] -> 0} to remove a conditionalEpression and get a numeral answer – Ahmed kh Oct 8 '17 at 18:58