What is -LRB- a + b -RRB- ^ -LRB- 1/2 -RRB- ?
If -LSB- math -RSB- a ^ 2 + b ^ 2 = 2 -LSB- / math -RSB- and -LSB- math -RSB- c ^ 2 + d ^ 2 = 1 -LSB- / math -RSB- then the value of -LSB- math -RSB- -LRB- ad-bc -RRB- ^ 2 + -LRB- ac + bd -RRB- ^ 2 -LSB- / math -RSB- is equal to ?