Example 1.2.12

> restart;

> with(linalg):

Warning, new definition for norm

Warning, new definition for trace

> X:=vector(2, [10^5*cos(Pi/12), 10^5*sin(Pi/12)]);

> Y:=vector(2, [2*10^5*cos(theta), 2*10^5*sin(theta)]);

> Z:=simplify(evalm(X+Y));

> Z[2];

> solve(Z[2]=0, theta);

> evalf(%,20);

> evalf(arcsin(-1/2*sin(Pi/12)), 20);

By changing the radian to the degree!

> evalf(%*(180/Pi), 20);