Please tell me the solution and the steps required to get solution to this.
Let sin(a)= 1/ sqrt(5) 0 < a < 90 degrees
cos(b)= 3/ sqrt(10) 0< b <90
then what is sin(a+b) equal to?
I had forgotten to clarify that I must do this all without a calculator, making the suggestion by anonymous kinda mood. I must thanks pickles thought because now I can solve any problem that is similar, I suppose then there are similar identities for say sin(a-b) and the sort, right?