If a and b are the measures of two first quadrant angles and sin a = and sin b = ,

find sin (a + b).

Use the identity:

sin(a+b)=sin(a)cos(b)+cos(a)sin(b)

Good to know also:
sin(a-b)=sin(a)cos(b)-cos(a)sin(b)
cos(a+b)=cos(a)cos(b)-sin(a)sin(b)
cos(a-b)=cos(a)cos(b)+sin(a)sin(b)

Use the addition formula:

sin(a+b)=SinACosB+sinBcosA

cosA= sqrt (1-sin^2 A)
cosB= sqrt (1-sin^2 B)

To find sin(a + b), we can use the trigonometric identity for the sine of the sum of two angles:

sin(a + b) = sin(a) * cos(b) + cos(a) * sin(b)

Given that sin(a) = and sin(b) = , we can substitute these values into the formula:

sin(a + b) = * cos(b) + cos(a) *

Now, to compute sin(a) and sin(b), we need information about the measures of the angles a and b. The question does not provide these values, so we cannot solve for sin(a + b) without additional information.