Search results

Any stats experts out there who can help me with this question? For anyone familiar it looks like a fairly common question where you are given two bits of information and use it to find the mean and s.d. So its easy enough to interpret the second bit ( 1 in 8 take less than 35 minutes) and...

It turns out the resulting quadratics is y=2x^2 This is how i did it but it feels like there might be a neater solution so i'd be interested if anyone has the time/inclination for alternative approaches! SPOILER BELOW... ( I have missed out some steps for brevity) Let P be a point on the...

Can anyone offer any thoughts on this problem please?

Can anyone offer an explanation as to why the following works. It feels like there is some dodgy maths going on ...

I have tried the various theorems and still getting nowhere, i am wondering if the question has enough in it?

Thoughts on this question please? My query is this: Can you go to the second step of the student proof from the first step? Something doesn't look right in the squaring? squaring the inequality is only valid when sin x - cos x > 0...which it is because the angle is obtuse. But can you just...

Ok, i am going around in circles here... How do you prove that the derivative of e^x is e^x? If you do it by first principles, you need a result ( namely the lim of (e^h-1)./h as h tends to zero is 1) and this result appears to depend on what we are trying to prove? Unless anyone can offer me...

I cant get this one to work... can someone spot where my reasoning has gone wrong?

I recently came across this pattern: 2^2+3^2+6^2 is a perfect square. 3^2+4^2+12^2 is a perfect square. 4^2+5^2+20^2 is a perfect square I can prove this algebraically starting with this kind of idea: n^2+(n+1)^2+n^2 (n+1)^2 Does anyone have a more elegant proof? Or perhaps a picture...

Good short video about James Maynard https://www.maths.ox.ac.uk/node/60744 Fascinating work on primes. I just wonder how these big brains connect things together. He talks about a Eureka moment.

Can someone help clarify some confusion? I can accept ( and develop, prove even ) the Binomial expansion for positive n: (x + y)^n = nC0 0 x^n y^0 + nC1 1 x^n - 1 y^1 + nC2 2 x^n-2 y^2 +.....+ y^n The series will always terminate. How do we know we can use this formula with negative/...

Can anyone see how you can get length AM=3? I am thinking there is something not right with the question, i have been using Pythagoras but getting stuck. Something doesn't feel right. I dont have much to post but be interested in starting points/suggestions rather than complete methods please...

Consider this problem... Its relatively easy to get started and i have got this far: The tiny square is obv 2, but what next? Algebra or is there an additional insight someone can suggest? I think its a famous problem so the solution is out there but more interested in knowing what to do!

Is there a way of finding the derivative of sin x without using first principles and therefore the limits that sinx \approx x and cosx \approx 1 ? Dont ask me why but i want to use the fact that sinx differentiates to cosx to show that the gradient of the tangent at x=0 is 1 so the equation of...

When multiplying fractions with mixed numbers, the standard approach is to convert both to improper fractions and then multiply in the usual way. However, how do you explain/convince a 10-year-old the following method ( which some tend to opt for) is wrong, rather than just tell them it...

I am looking at finding the range of the f(x)= x+1/x One obvious way is to use calculus: f'(x) = 1-1/x^2 , find the turning points and we get the range is f(x)>=2 or f(x)<=-2 Does the following alternative method make sense? x+1/x to be rewritten as (sqrt(x)- i/sqrt(x) )^2 +2 , a sort of...

How would you challenge this reasoning about adding fractions? A student sits a test comprised of two papers. They get 9 out of 10 in the first paper, written as 9/10 and 6 out 10 in the second paper (6/10). What do they get in total? i.e. 15/20 They conclude to add fractions it is ok to do...

I find the wording of the this question a bit complicated. Is it just after a counter example? can i just say n=0? Or if c isn't 1 , then you can just use n=c ? I am entirely sure i understand the question? Can anyone offer an interpretation?

Any thoughts on how to pull part and deal with the underlying cause ? 3.7x10 = 3.70 Presumably, it has arisen because of remembering a rule to do with 'add a zero' when multiplying by 10. So I am wondering should that even be taught? And are we doing something wrong when teaching young...

Been working on a problem with my 11 year old. It was to find the probability that a three digit number ending in 6, will be a multiple of 6? Intuitively what do you think this will be? Before reading on? 1/2, 1/4 ? Anyway, the way we looked at it was to think about the first 10 or so 3 digit...