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The diameter of a metal ring is D and the coefficient of linear expansion is y. The temperature of the ring is increased by 1 degree Celsius. What is the increase in area of the ring?

I solved it the following way:

Coefficient of superficial expansion = 2y

Initial area of the ring(A) = [(pi)D^2]/4

Increase in diameter of the ring = Dy

Increase in area of the ring = A x (2y)

= [(pi)D^2]/4 x 2y

= [(pi)(D^2)y]/2

But the answer given in my book is 2(D^2)y. Please help. Here the symbol ^ stands for power.

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# Homework Help: What is the increase in area of the ring?

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