The area between x-axis and curve y = cos x when 0 ≤ x ≤ 2π is

Let area be A.

So, area A is –

A =

Now, cos x is positive from x = 0 to x = π/2 and from x = 3π/2 to x = 2π and negative from x = π/2 to x = 3π/2.

So, A =

=

= [1 – 0] + [-(-1) + 1] + [0 – (-1)]

= 1 + 1 + 1 + 1

= 4 (Ans)

1