hi debjit625

I don't think that quadratic is correct. If you square the equation you have

So where did the sinxcosx term go ?

You could try this:

and so get an expression for cos(x - y) where cos(y) = 6/10 .....

This enables you to work out values for a and b and hence sin(a+b).

I'm getting

I feel as though a solution should be possible without evaluating the angles and thus giving 'absolute' accuracy but I cannot find it yet. Still thinking about this.

Bob

ps. Diagram was for a failed solution, but I cannot delete it at the moment.