Question

Using integrals, find the area of the circle x2+y2=1 ?

Answer 1

4( integral 0 to 1(

$\sqrt{1 - {x}^{2} } dx$

$= 4( \frac{x}{2} \sqrt{1 - {x}^{2} } + \frac{1}{2} sin \: inverse x)0 \: to \: 1$

$4(0 + \frac{1}{2} . \frac{\pi}{2} )$

$= \pi \: squre \: units$