Recent content by Sethric
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Calculating the Frictional Force on a 15kg Mass at 30°
Correct.- Sethric
- Post #14
- Forum: Calculus and Beyond Homework Help
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Volume bound by rho=2+2cos phi
You will need to go all the way to pi for phi. Your theta bounds are correct. You don't need to worry about visualizing it - you know the volume differential: \int dV = V- Sethric
- Post #4
- Forum: Calculus and Beyond Homework Help
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Volume bound by rho=2+2cos phi
You are missing a sine in your volume differential. Otherwise, what is the question? What work have you done on it so far?- Sethric
- Post #2
- Forum: Calculus and Beyond Homework Help
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Calculating the Frictional Force on a 15kg Mass at 30°
No, mass is not a vector. Your two vectors will be a unit vector pointing in the direction of the ramp and a weight vector pointing down. The weight vector will have a magnitude of (9.8)(15) = 147 (Newtons, if it matters).- Sethric
- Post #12
- Forum: Calculus and Beyond Homework Help
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Calculating the Frictional Force on a 15kg Mass at 30°
The reason you get a vector is that you are looking at a projection along a vector. In this case, you would be multiplying your scalar projection by a unit vector in that direction. Just because your terms matched the magnitude of a cross product, does not mean you have a cross product. You...- Sethric
- Post #10
- Forum: Calculus and Beyond Homework Help
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Calculating the Frictional Force on a 15kg Mass at 30°
Umm, that is the correct answer, but not the correct method. You shouldn't need the cross product. You defined mass as a vector, and then gravity as a vector, and then said they point in different directions. That is incorrect. Mass is a scalar, force from gravity is a vector. You want to find...- Sethric
- Post #8
- Forum: Calculus and Beyond Homework Help
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Power Series Expansion Homework: Multiplication & n-k Addition Method
There should be a double sum there, with a sum over k from k = 0 to n. Then you should be able to just solve what that sum would be.- Sethric
- Post #2
- Forum: Calculus and Beyond Homework Help
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Finding the Critical Value of IVP: 'Given DE
The way I have seen this is: In a more generalized form in first order (y' = f(x, y)), if there exists a solution that serves as a boundary between two classes of solutions to the differential equation that behave differently, then that solution is called a separatrix. I don't think I have seen...- Sethric
- Post #2
- Forum: Calculus and Beyond Homework Help
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Infinite geometric series application (long)
I see, you are talking about part 1. Well then, use your initial values. You know that the form will be y = y0 e-ct. You know that y0 = 240. Next, y4 = .4*240 = 96. That can solve for c.- Sethric
- Post #4
- Forum: Calculus and Beyond Homework Help
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Find limx-> 0 [(ex-1-x)/(x*sin(x))]
Have you considered trying L'Hospital's Rule?- Sethric
- Post #2
- Forum: Calculus and Beyond Homework Help
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Infinite geometric series application (long)
Try writing out the amount of the drug in the body at each time. At time t0, there will be 240 mg. At t=4 there will be 240 mg (next dose) + .4*240 mg (last dose). At t=8, 240 mg (next dose) + .4*240 mg (previous dose) + .4*.4*240 mg (first dose). What does the pattern look like? Can you write...- Sethric
- Post #2
- Forum: Calculus and Beyond Homework Help
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Calculating the Frictional Force on a 15kg Mass at 30°
Hmm, weird. OK. Then you will want to find the projection of the force due to gravity on a vector that points down the ramp. That will require a dot product. Recall projections?- Sethric
- Post #4
- Forum: Calculus and Beyond Homework Help
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Calculating the Frictional Force on a 15kg Mass at 30°
It would be easier to think of this in forces. The frictional force would be equivalent to the component of the force due to gravity that would point down the ramp, since they must cancel. Break gravity down to find that. Are you required to use a dot product here?- Sethric
- Post #2
- Forum: Calculus and Beyond Homework Help
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Let S={2−(1/n) :n∈N}. Prove that sup S=2.
Try proof by contradiction. Assume that there exists an upper bound less than 2.- Sethric
- Post #2
- Forum: Calculus and Beyond Homework Help
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Prove that p-group of order p^n is not simple
Partially correct. Assuming the center is a non-trivial proper subgroup of your p-group, then it is, by definition, normal - meaning your p-group is not simple. And it is required to be non-trivial. However, your center need not be a proper subgroup. If your center is the entire p-group...- Sethric
- Post #2
- Forum: Calculus and Beyond Homework Help