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1.7.14 Stationary points

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Question 42

The concentration of an enzyme, EEE micromoles per litre, in a bioreactor is monitored over a 6-hour cycle. The concentration at time TTT hours, where 0≤T≤60 \le T \le 60≤T≤6, is modeled by the equation:

E=T18(9+15T−2T2)+2 E = \frac{\sqrt{T}}{18}(9 + 15T - 2T^2) + 2 E=18T​​(9+15T−2T2)+2

Given that EEE has a stationary value at T=αT = \alphaT=α:

a.

Use calculus to show that α\alphaα satisfies the equation

10α2−45α−9=0 10\alpha^2 - 45\alpha - 9 = 0 10α2−45α−9=0
[4]
b.

Hence find the value of α\alphaα, giving your answer to 3 decimal places.

[2]
c.

Use further calculus to prove that EEE is a maximum at this value of α\alphaα.

[3]

1.7.14 Stationary points Questions

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