Recent content by overpen57mm

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    Show that ODE is homogeneous, but I don't think it is

    Ignoring the second part of the question for now, since I think it will be more clear once I understand how this equation is homogeneous. According to my textbook and online resources a first-order ODE is homogeneous when it can be written like so: $$M(x,y) dx + N(x,y) dy = 0$$ and ##M(x,y)##...
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    Off by order of magnitude when calculating how much calcium is in bone

    Yes, in fact having recently re-done the math with the more correct formula for initial Ca-48 mass $$N_1 = \frac {φ σ N_0 (1 - e^{-λt})} {λ}$$ Gives me a mass of Ca-48 of 36.8g, far too large to be 0.2% of anything with a maximum of 50g. I'm honestly beginning to think there's a typo in the...
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    Off by order of magnitude when calculating how much calcium is in bone

    ##2*10^{-28}m^2##, but ##2 * 10^{-24}cm^2##, because a m^2 is 10,000 cm^2.
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    Off by order of magnitude when calculating how much calcium is in bone

    Maybe I'm misunderstanding you, but according to all the calculators I have access to, ##166 / {1.63*10^{16}} = 1.018*10^{-14}##.
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    Off by order of magnitude when calculating how much calcium is in bone

    I think I have the answer, but when I calculate it out, I'm off by at least an order of magnitude. My process goes like this: The (looked up) specific activity of Ca-49 is ##1.63*10^7 TBq/g##, which is ##1.63*10^{16} KBq/g## The activity of the sample after 5 minutes rest is ##166KBq##, per...
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    Arc length of vector function - the integral seems impossible

    Thanks, I guess I was blinded by the derivative I got from the previous question.
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    Arc length of vector function - the integral seems impossible

    The vector equation is ## v(x)=(e^x cos(2x), e^x sin(2x), e^x) ## I know the arc-length formula is ## S=\int_a^b \|v(x)\| \,dx ## I found the derivative from a previous question dealing with this same function, but the when I plug it into the arc-length function I get an integral that I've...
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