Two equations of two unknown angles

If I have:

A = 87; B = 65; C = 73; D = 92;

And the two equations are:

D*sin(200)+A*sin(x)+B*sin(y)=0;73+D*cos(200)+A*cos(x)+B*cos(y)=0

How do I write a code to find x and y?

What is the solution to this error?

[Walter Roberson]

not eq space and then [list] but eq = and then the list

[Ravi N]

Thank you, however I still get the invalid expression error.

Answer 1

[John D'Errico]

First, I would recognize that you PROBABLY intended 200 to be a number in DEGREES, not radians. (200 radians would seem to make little sense.) Therefore, you need to use sind and cosd, not sin and cos.

Since you know how to use solve, (sort of) I'll do it that way.

syms x y
A = 87; B = 65; C = 73; D = 92; 
E1 = D*sind(200)+A*sind(x)+B*sind(y) == 0

E1 = 

E2 = 73+D*cosd(200)+A*cosd(x)+B*cosd(y) == 0

E2 = 

As you can see, sind and cosd convert the problem internally into one in radians. The x and y solutions will still be in the form of degrees though.

[xsol,ysol] = solve(E1,E2,x,y)

xsol = 

ysol = 

vpa(xsol)

ans = 

vpa(ysol)

ans = 

These will be angles in degrees, since I used sind and cosd. There are two primary solutions, but there are infinitely many solutions. We could add integer multiples of 360 degrees to those solutions.

[Ravi N]

Thank you for the help!!!

Answer 2

[David Hill]

fun = @solution;
x0 = [0,0];
I = fsolve(fun,x0);%solution 

function f = solution(x)
  A=87;B=65;D=92;
  f(1)=D*sin(200)+A*sin(x(1))+B*sin(x(2));
  f(2)=73+D*cos(200)+A*cos(x(1))+B*cos(x(2));
end

[Ravi N]

Thank you for the help !!!