Find the area of the region `{(x , y)\ : x^2+y^2lt=4,\ x+y\ geq2}`

Explanation

Let `R={(X,Y):X ^2+y ^2
≤4,X+Y≥2}`

`⇒R={(X,Y):X ^2+y ^2≤4}∩{(X,Y):X+Y≥2}`

i.e., `R=R_1 ∩R _2`, where
`R _1 ={(X,Y):X ^2+y ^2
≤4}`
and `R ^2= {(X,Y):X+Y≥2}`

For region `R _1`

​Obviously `x ^2+y ^2=4` is a circle having centre at` (0,0) `and radius `2`.

Since `(0,0) `satisfy `x ^2
...