Solution of simultaneous equations to get desired value
Solution 1:
Multiply the two equations by $\cos x$, ($x=200^\circ$ here), to get, $$d\cos x+c\sin x=a$$ $$c\cos x-d\sin x=b$$
Square and add. You may see the answer.
Solution of simultaneous equations to get desired value
Solution 1:
Multiply the two equations by $\cos x$, ($x=200^\circ$ here), to get, $$d\cos x+c\sin x=a$$ $$c\cos x-d\sin x=b$$
Square and add. You may see the answer.