Recent content by Taturana

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    Fire Truck Problem: Inertia, Effect & More

    This helped. Thank you very much.
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    Fire Truck Problem: Inertia, Effect & More

    Suppose a fire truck, with a huge tank of water. If the tank is half-full, when you slow down the water's inertia is going to push the truck forward. When it's full, the water can be thought like a solid, so it doesn't have the same effect. The question is: what are the concepts involved in...
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    Solving Statistics Problem: Proving at Least 2 People with Same Hair Count

    Homework Statement There is a city with 10 million people and an average human has 110 000 hairs. Prove that there is at least 2 people with the same amount of hair. The Attempt at a Solution I really have no idea of how to even start solving this problem. Sorry. Also, sorry for the...
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    Problem solving equation system

    Thank you for your response, rcgldr. I have tried simple substitution. Tried to come up with one equation of one variable from substituting, summing and manipulating the system's equations. But I could not get an equation of one variable, at least with the substitutions I tried. I don't...
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    Problem solving equation system

    Homework Statement Solve this equation system for x, y and lambda. \left\{\begin{matrix} 2x = \lambda (2x-6y)\\ 2y = \lambda(-6x-14y)\\ x^2-6xy-7y^2+80=0 \end{matrix}\right. The Attempt at a Solution I really tried A LOT of things, but I can't solve it. I think it is not helpful to post...
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    Transformers, its current and its resistance

    Hello, Suppose a simple transformer, not connected to a circuit (just to the home AC). If we get a multimeter and measure its resistance we will get a number. So if we plug it into the home AC, it will consume energy (constant power). Now suppose we have a desktop computer power supply...
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    Understanding how to reverse the integration order

    Not even the inverse function thing? Thanks!
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    Understanding how to reverse the integration order

    Thank you for the replies. It gave me a great advance. But I still have some questions. I notice that everyone when teaching this reverse order of integration thing tells: look at the figure, analyze it etc. 1 - Isn't there a RULE for finding the new OUTER bounds? By rule I mean an...
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    Understanding how to reverse the integration order

    Hello, I am talking about double integrals. I have seen many examples of how to reverse the integration order when current order is too difficult to calculate. But I still don't fully understand how to do it. I would like you to help me understanding this. Suppose the integral: ∫∫f(x,y)...
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    Proving the Positivity of Negative Times Negative: An Algebraic Approach

    I'm studying arithmetic of numbers. I want to understand why the product of, say, -3 for -4 is 12 and not -12. Thanks
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    Proving the Positivity of Negative Times Negative: An Algebraic Approach

    What's the proof for a negative number times another negative number gives a positive number? Thank you
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    Difference between Inner Product and Dot Product

    Could someone explain me the difference between the inner product and the dot product? Thanks all
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    Trying to understand why integration is inverse of differentiation

    Ahh, I see. But it does not tell me why the derivative is the inverse of antidifferentiation, does it? Thank you again.
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    Trying to understand why integration is inverse of differentiation

    Thank you all for the replies. Yes, I understand, and it does help a little bit. But, generally, you only said what I said in my post. What you said proves that there is a intrinsic relation between the integral and the derivative. But it does not prove that the derivative is the inverse...
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    Trying to understand why integration is inverse of differentiation

    Greetings, We know that the two operations (integration and differentiation) are inverse. I mean, if you integrate a function and differentiate the result of the first operation you go back to the first function. But I'm trying to understand WHY. Of course there are a lot of mathematical...
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