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 one year ago
A person scores f(x) = 90/1 + 4e^0.4t points on a test after t hours of studying. What does the person score without studying at all? Compute f’(0) and estimate how many points 1 hours of studying will add to the score.
 one year ago
A person scores f(x) = 90/1 + 4e^0.4t points on a test after t hours of studying. What does the person score without studying at all? Compute f’(0) and estimate how many points 1 hours of studying will add to the score.

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onegirl
 one year ago
Best ResponseYou've already chosen the best response.0This is what I did but my teacher said it was wrong she said ( Find f' and f'(0).) F(x) = 90/ 1 + 4e^0.4t F(0) = 90/ 1 + 4e^0.4(0) = 18 F(1) = 90/1 + 4e^0.4(1) = 24.45 So comparing the scote at f(1) and f(0) where at f(1) studying for 1 hour and f(0) studying none. F(1)  f(0)/24.45 – 18 = 6.45 points

EulersEquation
 one year ago
Best ResponseYou've already chosen the best response.1Should this have parenteses or not? Is this F(x) = 90/ (1 + 4e^0.4t )?

onegirl
 one year ago
Best ResponseYou've already chosen the best response.0like this \[\frac{ 9 }{ 1 + 4e ^{0.4t}}\]

EulersEquation
 one year ago
Best ResponseYou've already chosen the best response.1Your teacher specifically said to differentiate?

onegirl
 one year ago
Best ResponseYou've already chosen the best response.0she said to Find f' and f'(0)

onegirl
 one year ago
Best ResponseYou've already chosen the best response.0@EulersEquation so do you know how?

EulersEquation
 one year ago
Best ResponseYou've already chosen the best response.1Yes. I need to review this. First glance is to use the quotient rule. Do you know how to use the quotient rule? Someone else may want to take a look. I am in the middle of helping someone else. When I finish I'll get on it.

EulersEquation
 one year ago
Best ResponseYou've already chosen the best response.1Ha! I am terrible at arithmetic. On first run I get a negative number for f'(0). You cannot make a negative score on a test! Unless the teacher doesn't like you. I am rusty on this. I'll work on it some more. In the meantime, bump the problem and hopefully someone else will tackle this.

waterineyes
 one year ago
Best ResponseYou've already chosen the best response.1Just want to take derivative of that??

waterineyes
 one year ago
Best ResponseYou've already chosen the best response.1It will come out to be negative..

onegirl
 one year ago
Best ResponseYou've already chosen the best response.0what will come out? so what i did above is wrong or?

waterineyes
 one year ago
Best ResponseYou've already chosen the best response.1Wait, let we do it first..

waterineyes
 one year ago
Best ResponseYou've already chosen the best response.1\[\frac{ 90 }{ 1 + 4e ^{0.4t}} = \frac{ (90)(1.6 \cdot e^{0.4t}) }{ (1 + 4e ^{0.4t})^2}\]

waterineyes
 one year ago
Best ResponseYou've already chosen the best response.1It will become positive now.. :)

EulersEquation
 one year ago
Best ResponseYou've already chosen the best response.1Yeah. I don't see why it has to be differentiated  not according to the question.

waterineyes
 one year ago
Best ResponseYou've already chosen the best response.1Am I right in this?

EulersEquation
 one year ago
Best ResponseYou've already chosen the best response.1Ah! I forgot to square the denominator!

EulersEquation
 one year ago
Best ResponseYou've already chosen the best response.1That looks good.

waterineyes
 one year ago
Best ResponseYou've already chosen the best response.1So you can now find f'(0) by putting 0 as value of t..

waterineyes
 one year ago
Best ResponseYou've already chosen the best response.1@onegirl can you go for that?

onegirl
 one year ago
Best ResponseYou've already chosen the best response.0just plug in 0 and solve right?

waterineyes
 one year ago
Best ResponseYou've already chosen the best response.1Yep, just simple calculations with calculator..

waterineyes
 one year ago
Best ResponseYou've already chosen the best response.1Good.. Keep it up..

onegirl
 one year ago
Best ResponseYou've already chosen the best response.0i got 0 after i solved
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