Mark the correct alternative in the following:

If tan 69^o + tan 66^o – tan 69^o tan 66^o = 2k, then k =

Mark the correct alternative in the following:

If A – B = π /4, then (1 + tan A) (1 – tanB) is equal to

Mark the correct alternative in the following:

The maximum value of is

Mark the correct alternative in the following:

If and tan A tan B = 2, then

Mark the correct alternative in the following:

If and then α + β is equal to