=

If sin^-1 x + sin^-1 y = , then the value of cos^-1 x + cos^-1 y is

An urn contains 6 balls of which two are red, and four are black. Two balls are drawn at random. The probability that they are of different colours is

What is the distance (in units) between the two planes 3x + 5y + 7z = 3 and 9x + 15y + 21z = 9?

The equation of the line in vector form passing through the point (−1,3,5) and parallel to line , z = 2. Is