If A is the area between the curves y = sin x and x-axis in the interval $[0, \frac{\pi}{4}]$, then in the same interval, area between the curve y = cos x and x-axis is

1 - A

$A=\int\limits_0^{\pi / 4} \sin x d x=1-\frac{1}{\sqrt{2}}$

$A_1=\int\limits_0^{\pi / 4} \cos x d x=[\sin x]_0^{\pi / 4}=\frac{1}{\sqrt{2}}=1-A$

Hence (3) is the correct answer.