(sin a - cos a)^2 + sin 2a

Expanding the square:

(sin^2 a - 2sin a * cos a + cos^2 a) + sin 2a

Since sin^2 a + cos^2 a = 1:

(1 - 2sin a * cos a) + sin 2a

Expanding sin 2a using the double angle identity:

(1 - 2sin a cos a) + 2sin a cos a

Simplifying the expression:

1