Homework Help
For assistance with (but not answers to) homework problems.
A simple reminder to all: this is the "Homework Help" forum, not the "Homework Answers" forum. We will not do your work for you, only point you in the right direction. Posts that do give the answers may be removed.
5178 topics in this forum
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i need assistance on what models or protocols to use for enzyme assay such as catalase (using a microplate reader), glutathione, superoxide dismutase, myeloperoxidase and lipid peroxidase. i want t know how to do these assays without the use of enzyme kits but use of buffers and how i would prepare those buffers and also how to prepare my samples for these assays.
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Ok. I'm having a very difficult time with this problem. I can't even do this first part. Any help would be greatly appreciated. Like what steps I should take, what method to use, whether or not to become a lit. major, ect., ect. Here it is. Part 1. We seek to solve the time-independent Schrodinger equation: [math] \frac{-\hbar^2}{2m} \frac{d^2\psi}{dx^2} + \frac{1}{2}m\omega^2 x^2 \psi = E\psi [/math] First, introduce the dimensionless variable: [math] \xi = \sqrt{ \frac{m \omega}{\hbar}}x, [/math] and show that the Schrodinger equation becomes: [math] \frac{d^2 \psi}{d \xi^2} = (\xi^2 - K) \psi, [/math] where K is the energy in units of [math…
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Hi i have this question and I need some help with it, can anyone point me in the right direction? need to know the formula for calculating this. 1. Calculate the mass (in g) of sodium acetate required to prepare 100 ml of 0.1 molar solution (sodium acetate molecular weight 82.03). How do you go about calculating these type of questions ? thanks in advance
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Hi all I have a question which I am confused about I really dont know how to work it out. A total of 981 patients were tested. 10% of patients had a positive result of which 70 were actual true positives. Out of the population reporting a negative result, 95% were actually true negatives. Calculate the sensitivity and specificity. Ok i have the formula for calculating sensivity and specificity and know how to calculate them but, i dont know how to get the numbers of true positives, false positives, false negatives and true negatives from this kind of data. Can anyone help please thank you .
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Please guide me in solving this problem:Find 'n' in the unit vector 1/10(4 icap+8 jcap+n kcap). The answer at which I arrived is root 20 but the one given in the book is root 0.002 .Please tell me if I am correct and if i am wrong guide me in solving this problem.
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In my GEN BIO 1 course we just did cell division. I breezed through the chapter since it was a nice review from AP Biology. All of the sudden, when I got to lecture, though, I was slammed with confusion. On my professors powerpoint, for mitosis she had labeled Interphase as going from 2n--->4n. This made no sense to me. Isn't the DNA replicated in S phase, and the number of chromosomes remains the same? So for instance, if this was a human cell and there were 46 chromosomes, wouldn't this indicate that there are now 92 chromosomes (4n)? 92 chromatids, yes, but chromosomes? Seems weird. For prophase all the way to telophase she has "4n" underneath each phase picture…
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Hi i was un sure if this is right is it ? the sun is the source of energy for all foods. only plants can produce their own food . this is called ___________ and we can test for it using iodine, this turns blue black in the presence of ____________. i didnt now some of it is it right ?
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I am having issues trying to understand how to calculate some probability problems. I understand that I can not be given the answer - I would not want that anyway. I need to know how to get the answer so that I can do the rest of the questions like it. the problem is as follows: 10 composite samples are used to run a composite test, and the probability that any one sample will test positive is 0.0400 what is the probability that the composite sample will test NEGATIVE? What is the Probability that composite sample will test POSITIVE? HOW DO I FIND THE ANSWER, in layman's terms please. I am a stats student right now.
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Hey guys. I'm going over my notes in class and I probably missed something the professor said, because one of the steps makes no sense to me. I was hoping someone could give me a hint on what's going on. We're doing basic non-degenerate perturbation at the moment, and in this case we examined the first-order correction for the harminic oscillator with H1 defined as [math]\lambda x^4[/math] So, H0 is obvious (the usual solution for the harmonic oscillator), but then we move on to try and get the H1 correction. My professor used a(dagger) and a for it. [math]H_0=(a a^{\dagger}+\frac{1}{2})\hbar \omega[/math] Ground States a|0>=0 [math]N=a^{\dagg…
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So for my mechanics class we have these two problems on our online homework: "An object in the shape of a thin ring has radius A and mass M . A uniform sphere with mass m and very small radius is placed with its center at a distance x to the right of the center of the ring, along a line through the center of the ring, and perpendicular to its plane. What is the magnitude of the gravitational force that the ring-shaped object exerts on the sphere?" and "A thin, uniform rod has length L and mass M. Calculate the magnitude of the gravitational force the rod exerts on a particle with mass m that is at a point x along the axis of the rod a distance from the c…
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Hi! I'm trying to work on a problem but it seems I'm really stuck and don't even know where to start. 148 students ride in 4 buses, which transport 25, 33, 40 and 50 students respectively. A student is chosen at random. Let X be the number of student on the bus she's riding. Also, one of the 4 busdrivers are chosen at random. Let Y be the number of students on his bus. Calculate expected values E[X] and E[Y]. (I've calculated expected values before but this question seems different and I'm really at a loss as to where to start.) Would really love some help with this!
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1. The problem: A new savings account with an initial balance of zero is made. You save money continuously, at a rate of $500 per month. Also, every month you plan to increase this rate by $5. you've found a bank account that pays continously compounded interest at a rate of 8% per year. Estimate how long it will take for you to save one million dollars. 2. The attempt at the solution: I decided to take care of the saving rate first: since my interest is per year I decided to convert the savings to a yearly rate as well where k=500*12=6000, then I had to take care of the increments so I write it as 6000+60t where 60 is found by 5*12, and the t is in years so that e…
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Does anyone know the approximate number of insulin receptors present in a liver cell? I've been looking on the net, but haven't found a figure. Any help, even if it's just to direct me to a site that might help me in this? Thanks in advance!
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I'm having difficulty answering a question for my pre-lab, it goes "What would be the most appropriate wavelength of light with which to perform spectophotometry on a solution that is purple in color? Explain your answer." I had received help from friends, out idea had to do with yellow light, since it is a complement to purple. But with that, even we weren't certain. And I'm not sure how to explain why that light is the "most appropriate". Would it be because it can travel through the substance the easiest? I'm not sure. Your help would be greatly appreciated.
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i don't know how to answer this without going to the lab! 1. What is a benefit and one disadvantage of observing bacteria in Yogurt using a live whole mount compared to a Gram stain slide?
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For my post-lab in Chem, I cannot find the information relating to the melting and boiling points of the following ions: Ammonium (NH4^+) and Carbonate (CO3^2-). Does anyone have this relevant information? We are supposed to find outside sources, but I didn't come across any thus so far.
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Hey again, I'm dealing with QM and the subject is entirely new to me. I'm having troubles figuring out how to start the questions. Here's another in my frustrated series: Problem 2: If U is a unitary matrix, show that the absolute value of every matrix element is less than or equal to 1, ie: [math]|U_{ij}|\leq 1[/math] So in this case, here's how I start my solution (couldn't find the 'cross' symbol, so I'll use * instead): U is a unitary matrix, so [math]U^{*}U=UU^{*}=I_n[/math] and [math]U^{*}=U^{-1}[/math] And so, I started: [math]UX = \lambda X[/math] [math]U^{*}UX=U^{*}\lambda X=\lambda U^{*} X[/math] [math]I_{N}X=\lambda U^{*} X[/math] An…
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Just on the last two questions of my physics homework, and I really don't understand them! They're topics we haven't covered yet, the teacher just said have a go at them but I really don't understand them. 1, A barge of total mass 300kg is pulled by a single rope attached to a tugboat of mass 1000kg. If the drag on the tug and the barge is one-tenth of their respective weights, and the total forward force exerted bt the tug is 5130kg force, find the magnitude of: a, the total force resisting the forward motion of the tug and barge (is this just 30kg + 100kg?) b, the acceleration of the tug/barge system c, the unbalanced accelerating force on the barge ? …
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I'm doing a lab report for an experiment about gas laws for my college chemistry class. One question is, "Use P total = P atm = P gas + P water to calculate the partial pressure of the butane gas collected." How would I figure out this problem? I also have P atm = 0.9733 atm, volume of gas is 94.2 mL, temperature is 21 degrees C from my data if this helps. Thank you!
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i keep getting stuck in some problems of physics because the differential equation of the form a dy/dx + by = c f(x) keeps cropping up. is there any general method to solve this differential equation? when f(x) is sinusoidal, we avoid it using j operators and get the solution but in my particular problem f(x) is exponential.
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Hello everyone. I have an urgent electricity question which can be viewed in the attachment. The question is: Calculate a)the current in the main circuit b)the p.d. across the 4 ohms resistor c)the current through the 12 ohms resistor For part a), What I did to find the total resistance is to find the resistance of the resistors connected in parallel first. So 1/R = 1/4 + 1/12 gives 3 ohms. Then I would add 3 ohms with 7 ohms, which would be equal to 10 ohms - that is the total resistance of the circuit. Now I have to apply Ohm's law - I = V/RI = 20V/10R =2A Can anyone please help me in part b and c? Thank you so much!
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I am just a bit confused about whether we should use a truncated value in calculation, personally I think the answer should be 'no' (as multiple rounding-off or truncation adds uncertainty), but I just want a confirm. Say for example, I worked on raw data and got an eqation of: y = 0.784x(plus or minus 0.002)+0.059(plus or minus 0.008), so here 0.784 and 0.059 are truncated values based on the standard deviation (0.002 and 0.008). Now if y is 0.224, shall I use the raw values (that is, the original values not truncated) or truncated values of 0.784 and 0.059? If if use the truncated ones, then, 0.224 = 0.784x+0.059, x=0.210(3 sig fig). I just feel a little bit weird no…
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Hey guys, I got a homework assignment I'm having a lot of trouble with. This is post #1, I'll post a few more regarding the other problems in the homework. I'm not looking for an answer, I'm looking for assistance in how to proceed. This is new to me and very confusing, and my confidence in QM is very low after last semester's course (we all failed, if you remember... had a makeup test that also didn't go well, but I ended up getting a C+, which I usually consider as failure, but in this case, at least it's *passing*... err) Anyways, problem 1: If A,B are two linear operators on a Hilbert space, show that a^(A) B e^(-A) = B + [A,B] + 1/(2!) [A,[A,B]] + ..…
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Last question for this series. I started answering this one and got stuck. Again, this subject is new to me, so forgive me if I miss obvious stuff.. I'm getting used to the format and the method. I don't want to copy an answer, of course. I would appreciate an explanation and/or a way to continue so I can go on to other similar problems and also understand how to solve these type of questions in the future. Thanks! Problem 3: The Hamiltonian for three-dimensional system is of the form: [math]H=\frac{p_{i}p_{i}}{2m}+V[/math] where V depends only on r. Obtain the commutator [math] [x_{k}p_{k},H][/math] -- Here's what I have so far: [math] […
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