31.
a) Let c₁ = 1 and c₂ = 2, find c₃ which makes  coplanar.
b) If c₂ = –1 and c₃ = 1, show that no value of c₁ can make  coplanar.

Find the area bounded by the circle x² + y² = 16 and the line √3y=x in the first quadrant, using integration.

Using integration, find the area of region bounded by the triangle whose vertices are (–2, 1), (0, 4) and (2, 3).