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• Yesterday, 11:17 PM
What is the derivative of a/x? (Not of ax!)
3 replies | 53 view(s)
• Yesterday, 11:03 PM
I think, if I'm interpreting your equations correctly, that you are asking how to get from \displaystyle -\frac{h^2}{2m} \frac{d^2\psi}{dx^2} +...
2 replies | 25 view(s)
• Yesterday, 03:21 PM
It will help a lot if you show the actual work, rather than just describe it. As it is, we can't be sure what you did, and whether you did it...
1 replies | 22 view(s)
• Yesterday, 03:11 PM
What was your answer? Maybe it is really correct. If you show us your table, and if necessary tell us how you filled it out, we can see if there...
3 replies | 37 view(s)
• Yesterday, 02:41 PM
Please quote the entire problem as given to you. Words matter a lot in probability problems. The first part is only 1/8 (which I think you meant)...
1 replies | 36 view(s)
• Yesterday, 02:37 PM
I'm sorry for the long delay in replying; newcomers' questions often hide among others due to the delay in posting for moderation. I don't...
2 replies | 42 view(s)
• Yesterday, 02:29 PM
Please show your work, so we can see whether you made a mistake, or just didn't go far enough. How do you know you are not "getting the answer"? (Do...
3 replies | 53 view(s)
• Yesterday, 10:22 AM
Not quite. In effect, you just ignored the individual probabilities of an error for each desk, and gave back the percentages for choosing each desk....
9 replies | 175 view(s)
• Yesterday, 10:18 AM
I don't understand. How can you be getting a specific value with no specific values for A or B or c? You are supposed to show that |\tan A-\tan...
7 replies | 98 view(s)
• Yesterday, 10:08 AM
One example doesn't prove it is always true. You can guess that, since you were told to try an example, you were expected to discover a...
7 replies | 98 view(s)
• 09-17-2018, 11:35 PM
I went back and tried to check this, and I don't even know what it means. If I'm reading it correctly, x = (1+1/z)^z (z/(1+z))^z simplifies to x =...
14 replies | 255 view(s)
• 09-17-2018, 09:08 PM
Do you mean, how to find the limits of integration? It would be helpful if you showed the parts you can do (and your efforts at everything) so we...
1 replies | 48 view(s)
• 09-17-2018, 06:04 PM
Before we can help, we really need to know what help you need. Do you know what eight-bit twos complement is? Are you having trouble converting in...
2 replies | 40 view(s)
• 09-17-2018, 06:02 PM
What I asked was not how you are calculating the HCF, but how you are defining the HCF of two non-integers: What does it mean that c is the HCF of a...
3 replies | 100 view(s)
• 09-17-2018, 01:14 PM
I take it you have reason to think the MVT might be relevant, such as that you just learned about it. You're right; it is. What would the MVT say...
7 replies | 98 view(s)
• 09-17-2018, 10:28 AM
This is not true of all angles, so you have to start with something specific about 10°, and then try to use identities to obtain the desired fact. ...
2 replies | 54 view(s)
• 09-17-2018, 09:08 AM
So, you have been able to prove that claim for yourself, since no proof is given? I'm not saying it's wrong, just that math is not a matter of...
14 replies | 255 view(s)
• 09-16-2018, 11:17 PM
Where did this come from? Did you find some source that gives you this "general form", or did you derive it? I'd like to see this. I think an...
14 replies | 255 view(s)
• 09-16-2018, 05:38 PM
You're missing a negative, and you didn't completely apply the chain rule. Notice that the exponent is not just -Bt, but -Bt^2.
3 replies | 108 view(s)
• 09-16-2018, 05:28 PM
An alternative way to do this is to calculate the slope of each segment, and see if any two are perpendicular. This is often easier than calculating...
3 replies | 78 view(s)
• 09-16-2018, 12:12 PM
Yes, I was in a hurry, and didn't take the time to proofread. I've fixed that detail. There's still a lot more to say about both this equation and...
14 replies | 255 view(s)
• 09-16-2018, 07:58 AM
No, you're missing some important points. (I don't have time now, so I'm not looking at your handling of the derivative, only at whether it is a...
14 replies | 255 view(s)
• 09-15-2018, 10:23 PM
As has been said, this can't be solved by typical algebraic methods (because the variable appears both in the exponent and outside the exponent),...
5 replies | 143 view(s)
• 09-15-2018, 10:18 PM
Are there additional conditions you have omitted, such as that x and y must be integers? That would make it a somewhat more interesting problem.
5 replies | 134 view(s)
• 09-15-2018, 10:16 PM
You must go further. Collect terms with y on one side: y <= (8/5)y becomes 0 <= (8/5)y - y, which is 0 <= (3/5)y. What do you do next?
6 replies | 117 view(s)
• 09-15-2018, 10:14 PM
Shahar's response to me appeared to confirm the other interpretation, that it is about the number of each, rather than lengths. But until we hear...
7 replies | 121 view(s)
• 09-15-2018, 05:44 PM
I'm a little confused. What are you saying your calculator can't do? I showed you that it can do not only base 10 and base e logs, but also any base,...
6 replies | 113 view(s)
• 09-15-2018, 03:27 PM
You can only divide numbers. Infinity is not a number. So you can't divide infinity by infinity. You can't do any division involving infinity without...
7 replies | 121 view(s)
• 09-15-2018, 03:02 PM
I'm not sure what you are asking. Any circle has infinitely many chords (i.e. segments joining points on the circle), of which infinitely many are...
7 replies | 121 view(s)
• 09-15-2018, 01:44 PM
I checked your calculator's manual (see pp. 18-19), and see that it can't solve equations, but it can calculate logs with any base. Do you see how...
6 replies | 113 view(s)
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I was a software engineer for many years, and have been teaching at a community college since 2004. Since 1998, I was a part of Ask Doctor Math (http://mathforum.org/dr.math/ and now http://themathdoctors.org/).
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