Changing the water levels of a lake

Kingyou123
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Homework Statement


Attached problem

Homework Equations


Anti-derivatives, linear approx. F(a)=f(a)+F'(a)(x-a)

The Attempt at a Solution


I'm stuck on the first part, I think (w')^-1(1)= W which is 1. It seems too easy... and for part c I'm having trouble finding the equation for the line. I figured that if I graph it on my calculator and use a regression test to find the equation
 

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The attachment is way too zoomed out for me to read. Can you type the problem statement into the forum? That would help... :smile:
 
berkeman said:
The attachment is way too zoomed out for me to read. Can you type the problem statement into the forum? That would help... :smile:
updated it, sorry for that.
 
Is your question just the part that is checked: "(b) Explain what item iv means in terms of the city, lake, and IES budget"?

Item iv is "(w^{-1})'(1)". Since w(t) is the depth of water in the lake at time t, w^{-1}(x) is the time at which the level of the lake is x. Then (w^{-1})'(x) is the rate at which time for the water to decrease amount x is changing.
 
HallsofIvy said:
Is your question just the part that is checked: "(b) Explain what item iv means in terms of the city, lake, and IES budget"?

Item iv is "(w^{-1})'(1)". Since w(t) is the depth of water in the lake at time t, w^{-1}(x) is the time at which the level of the lake is x. Then (w^{-1})'(x) is the rate at which time for the water to decrease amount x is changing.
My question is on part a, I'm confused what(w')^-1(1) is. Thank you for help with part B :)
 
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There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...

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