Comment by user2023861 on How to solve these equations for x and y..
My method was to put the equations in Excel and use the solver. It's not an enlightening method, but it gives you an answer right away. Ask your teacher if you can do this on a test :)
View ArticleComment by user2023861 on How to use a difference table to find a formula for...
Let Excel do the work. See my answer here: math.stackexchange.com/questions/935002/…
View ArticleComment by user2023861 on Solving $2^{2x+1} - 2^{x+4} = 2^3 - 2^x$
@quid Thanks. I thought that the method seemed wrong but I was surprised to get the right answer.
View ArticleComment by user2023861 on Find the value of this series
This reminds me of Rodney Dangerfield in Back to School: "The answer to question 1, part 15, subpart 7, section 3, subsection 11 is ... 6?"
View ArticleComment by user2023861 on Simple Trig Equations - Why is it Wrong to Cancel...
@Taemyr, oops. I guess I should have checked the possibility that a equaling zero solves the equation before cancelling it.
View ArticleComment by user2023861 on binomial problem : Executive Airlines
@albert, Probably, no, and it's 1/32.
View ArticleComment by user2023861 on Solving Systems of Equations
Just curious, does the fact that this has no solution mean that these lines are all skew to each other?
View ArticleComment by user2023861 on How to find irrational numbers between rationals....
Can you just take any known irrational number and add or subtract a rational number to it to get a result in the range? Given that sqrt(2) is irrational and roughly equal to 1.4, subtract 0.6 from it....
View ArticleComment by user2023861 on $21$ balls in a bag - Probability
I don't think this is right. Like you say, you have five options for the first ball. If your first ball is one of those five options, you then have four options for the second ball. If your first is...
View ArticleComment by user2023861 on $21$ balls in a bag - Probability
@BharadwajVemavarapu, your numerator is not double-counting, but your denominator is. While, for example, picking 17 and then 18 is gives the same outcome as picking 18 and then 17, they are still two...
View ArticleComment by user2023861 on Why does using elimination in a system of first...
"minus" is not a verb. Use "subtract" as in "I could then use elimination to subtract the top equation from the bottom one to get,"
View ArticleComment by user2023861 on Intuitively, why does Bayes' theorem work?
@Canada-Area51Proposal, Thanks. Why did you make a recent edit to my answer? Your edits don't add or elucidate any parts of it. After your edits, we're left with some awkward sentences like In the...
View ArticleComment by user2023861 on Why does adding a suitable multiple of $9$ always...
Why does adding a 1 or a multiple of 1 always lead to the reverse of the number? 17 + 1 + 1 + 1 + 1 + .... + 1 + 1 = 71
View ArticleAnswer by user2023861 for Baffled by resolving number list
FYI, you can easily find a polynomial equation that fits that sequence in Excel. This is probably not what the teacher is looking for, but it's really easy.Paste those numbers into a column in...
View ArticleAnswer by user2023861 for Probability that the sum of three integer numbers...
Here's a C# solution. My original (wrong) solution divided by 1000000. It was wrong because it counted cases with duplicate numbers. This version below divides by the correct number.static void...
View ArticleAnswer by user2023861 for Disproving existence of real root in some interval...
It's sufficient to show that:f(1) > 0For all n > 0: f(1 + n) > f(1) Step #2 means that the function is increasing at all points to the right of x=1. From this you can say that f(x) doesn't...
View ArticleAnswer by user2023861 for Interesting Question on Ants
This should help arrive at the answer. Let's first consider the shortest amount of time you'd have to wait. Assuming the ants were evenly distributed, and each ant faced the nearest edge, you'd have to...
View ArticleAnswer by user2023861 for Prove that $1 + 4 + 7 +···+ 3n − 2 = \frac {n(3n −...
Here is @Shooter's answer shown a different way. Let's take the example of n = 8:1 + 4 + 7 + 10 + 13 + 16 + 19 + 22 = 92Let's rearrange this and group:(1 + 22) + (4 + 19) + (7 + 16) + (10 + 13) = 92Now...
View ArticleAnswer by user2023861 for If both $a,b>0$, then $a^ab^b \ge a^bb^a$
There are three cases: $a = b$, $a \lt b$, and $a \gt b$. The inequality is trivial when $a = b$, and the case where $a \lt b$ is really the same as the case where $a \gt b$. So lets just consider the...
View ArticleAnswer by user2023861 for Ordinary differential equation with Boundary value...
Let's assume $f(t) = c_1e^{c_2t}$It's given that $f(0) = 3$ so $c_1 = 3$.Differentiating gives $f'(t) = c_1c_2e^{c_2t}$Plugging in the differential equation: $f′(t)=2f(t)$ gives $c_1c_2e^{c_2t} =...
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