Determine the exact value of:

sin30° + cos225° + sin150° + cos330°

sin30° + cos225° + sin150° + cos330°

= sin30° + (-cos45°) + sin30° + cos30°
= 1/2 - 1/√2 + 1/2 + √3/2
= 1 - 1/√2 + √3/2