The equation of the curve is y = √(a2 – x2)
We can write it as y2 = a2 – x2
y2 + x2 = a2 ….. (1)
Here we know that x2 + y2 = a2 represents a circle having center at O (0, 0) and a units as the radius
Similarly x2 + y2 = a2 has even power of x and y and is symmetrical about x and y-axis.
So the required area = area of OAB