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標題:
發問:
The radius of a circular disc is increasing at a constant rate of 0.04 cm/s . Find the rate at which the area is increasing when the radius is 20cm.
最佳解答:
A = π r^2 dA / dt = 2 πr ( dr / dt ) dA / dt = 2π( 20 )( 0.04 ) dA / dt = 1.6π Hence the area is increasing at 1.6πcm^2 / s.
其他解答:
1.6πcm^2 / s
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A-Maths發問:
The radius of a circular disc is increasing at a constant rate of 0.04 cm/s . Find the rate at which the area is increasing when the radius is 20cm.
最佳解答:
A = π r^2 dA / dt = 2 πr ( dr / dt ) dA / dt = 2π( 20 )( 0.04 ) dA / dt = 1.6π Hence the area is increasing at 1.6πcm^2 / s.
其他解答:
1.6πcm^2 / s
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