Question 901286
We need to find sin alpha and sin beta.

cosine = adjacent over hypotenuse.

x^2 + 1^2 = 2^2

x^2 = 4 - 1

x^2 = 3

sqrt{x^2} = sqrt{3)

x = sqrt{3)

sin alpha = sqrt{3}/2

tangent = opposite over adjacent.

1^2 + 3^2 = x^2

1 + 9 = x^2

10 = x^2

sqrt{10} = sqrt{x^2}

sqrt{10} = x

sin beta = 1/sqrt{10}

We now plug and chug.

sin(A + B) = sin A cos B + cos A sin B

Let A = alpha and B = beta for short.

We have sin alpha and sin beta.

We need cos beta and cos alpha.

cos alpha = 1/2 and cos beta = 3/sqrt{10}.

Plug into formula and simplify.

Here is the formula you need:

sin(A + B) = sin A times cos B + cos A times sin B

Can you finish?