Q3 of 45 Page 1

Evaluate:

Let Δ =

By expanding the determinant about the first row.

Δ = cos 15° cos 75° - sin 75° sin 15°

We know that:

cos(A + B) = cos A cos B – sin A sin B

∴ Δ = cos (75 + 15)° = cos 90° = 0

Let A = {1, 2, 3}, B = {4, 5, 6, 7} and let f = {(1, 4), (2, 5), (3, 6)} be a function from A to B. State whether f is one-one or not.

If write A^–1 in terms of A.

If a matrix has 5 elements, write all possible orders it can have.