Posted by azeem on .
Find the approximate increase in the area of a circular disc if its diameter is increased from 44cm to 44.4cm

Calculus  linearization 
MathMate,
Since the exact increase can be calculated readily by
π(r2²r1²)
=π(44.4²44²)
=35.36π
I assume you are working on linearization in calculus.
Let
A(r)=πr²
A'(r)=2πr
Approximate increase in area
=A'(r)Δr
=2πr*Δr
=2π(44)(0.4)
=35.2π (approximately)