Let $$\alpha $$ and $$\beta $$ be two roots of the equation x² + 2x + 2 = 0 , then $$\alpha ^{15}$$ + $$\beta ^{15}$$ is equal to :

The area (in sq. units) bounded by the parabolae y = x² – 1, the tangent at the point (2, 3) to it and the y-axis is :

If $${\cos ^{ - 1}}\left( {{2 \over {3x}}} \right) + {\cos ^{ - 1}}\left( {{3 \over {4x}}} \right) = {\pi \over 2}$$ (x > $$3 \over 4$$), then x is equal to :

If y = y(x) is the solution of the differential equation,

x$$dy \over dx$$ + 2y = x², satisfying y(1) = 1, then y($$1\over2$$) is equal to :