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secondary 4 | E Maths
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Nur
Nur

secondary 4 chevron_right E Maths chevron_right Singapore

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Date Posted: 3 years ago
Views: 179
J
J
3 years ago
y = 0.057x - 0.001x²

dy/dx = 0.057 - 2(0.001)x
= 0.057 - 0.002x


Maximum for such a quadratic function is when dy/dx = 0

0.057 - 0.002x = 0

0.057 = 0.002x

x = 0.057 ÷ 0.002

x = 28.5


The splenic artery resistance is a maximum at 28.5 weeks (the 29th week)
J
J
3 years ago
Alternative :


For a quadratic curve with the formula y = ax² + bx + c ,

dy/dx = 2ax + b

when dy/dx = 0,

2ax = -b

x = -b/2a


here your a = -0.001 and b = 0.057


x = -0.057/2(-0.001)

= 0.057/0.002
= 28.5

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Kai
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