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MitsuShai

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**Uncertainty for a ratio (urgent help!)**

Question: As you eat your way through a bag of chocolate chip cookies, you observe that each cookie is a circular disk with a diameter of d = 8.32 cm +/-1×10−2 cm and a thickness of h = 9.3×10−2 cm +/-1×10−3 cm.

Find the uncertainty in this ratio of the diameter to the thickness.

Hint:Notice the division.

If we are dividing that is a negative exponent.

The ratio of the diameter to the thickness is 89.5. How can I use the calculus error prop./the partial derivative to solve this? The hint also made things more confusing.

Someone said to said it up like this or something: d*h^-1, but I still don't understand.

Plus, I don't see how you can get a ratio from the partial derivative formula. And I tried manipulating the volume formula: v=[(pi d^2)/4]*h, but it can't go to d/h...I was spending my time yesterday and today just to solve this problem and I couldn't figure it out and it was the only problem I had trouble with...sorry I'm very frusterated right now >:[

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