Secondary Maths questions, give me your maths questions

[Nasma]

I'm currently desperately searching for ways to procrastinate, so help me. If you have any maths questions, ask, and I'll do my best to answer. This means:

- Actual questions, i.e. "What is the integral of sin(x).exp(x)?"

- Explanations, i.e. "Why does the quadratic formula work?", "How can I tell the difference between continuous data and discrete data?"

- Tips, i.e. "What's a good way to stop making this mistake?"

- Anything else you can think of

If you can let me know if my response was helpful, that'd be great too.

Good luck on exams.

 

[mdc]

Sympathy post

Here's a nice spec. maths problem:

Take an arbitrary quadrilateral. Attach a square to each side such that the side-lengths of the squares are equal to the appropriate side-length of the quadrilateral. Pictorially:

Draw lines connecting the centres of opposite squares as shown above. Show that the lines have the same length and are perpendicular.

 

[scooterselwood]

If x+5=11 what is x?

 

[i_love_the_hoff]

If x+5=11 what is x?

......6

 

[Colin D'Cops]

If x+5=11 what is x?

That s**t I learnt in primary school.

Anyway, x = 6. (6 + 5 = 11)

 

[scooterselwood]

That s**t I learnt in primary school.

Anyway, x = 6. (6 + 5 = 11)

Im surprised you did learn, cause you were silly enough to think I was serious...

 

[Colin D'Cops]

Im surprised you did learn, cause you were silly enough to think I was serious...

Yeah cause it's easy to tell on a compter screen isn't it? Tool.

Wouldn't surprise me if you were actually serious to be honest.

 

[DamianBis]

x-9000=1

It's over 9000

 

[ToroHombre]

 

[Colin D'Cops]

Haha, nice find there.

 

[i_love_the_hoff]

pythagoras.....my favourite

 

[doggiesin08]

The complete FUNNY TEST can be found here: http://www.jimmyr.com/blog/Funny_Student_Exam_Answers_91_2007.php

 

[mdc]

The complete FUNNY TEST can be found here: http://www.jimmyr.com/blog/Funny_Student_Exam_Answers_91_2007.php

Good post.

 

[icetea]

prove that no 3 postive integer a, b, and c can satisfy the equation a^n+b^n=c^n for any integer value of n greater than 2.

 

[TheBigT]

prove that no 3 postive integer a, b, and c can satisfy the equation a^n+b^n=c^n for any integer value of n greater than 2.

still have bad memories of watching a video regarding that last year.

 

[icetea]

still have bad memories of watching a video regarding that last year.

haha same here, i find it amazing how such a seemingly easy problem was so hard to prove. it took this mathematician 7 years to work out a proof :S.

 

[mdc]

it took this mathematician 7 years to work out a proof :S.

"It took mathematicians around the world hundreds of years of failure before someone was able to prove it" would be closer to the mark.

 

[SJ]

Why does e^(pi*i) = -1?

 

[mdc]

Why does e^(pi*i) = -1?

e^(x*i) = cos(x)+isin(x)

e^(pi*i) = cos(pi) + isin(pi) = -1 + i*0 = -1

 

[SJ]

e^(x*i) = cos(x)+isin(x)

e^(pi*i) = cos(pi) + isin(pi) = -1 + i*0 = -1

That's right. Maybe "why" isn't the correct question, as I understand the algebra. I haven't studied mathematics since second year - how does e^(x*i) = cos(x)+isin(x) again?

 

[mdc]

how does e^(x*i) = cos(x)+isin(x) again?

You can think of it as a notational convenience, or otherwise expand cos(x), isin(x) and e^(x*i) as Taylor Series in the complex plane and see that it holds.

 

[SJ]

You can think of it as a notational convenience, or otherwise expand cos(x), isin(x) and e^(x*i) as Taylor Series in the complex plane and see that it holds.

That's it. Euler's identity is an amazing bit of mathematical beauty in any case.

 

[Colin D'Cops]

Euler's identity is an amazing bit of mathematical beauty in any case.

 

[SJ]

Don't get it.

If you mean that I don't know what I'm talking about, you're only half right. I've studied advanced first year maths and also second year engineering maths at university. I have written a proof on the identity before too, I just couldn't remember the principles behind it.

Thanks mcd.

 

[Colin D'Cops]

If you mean that I don't know what I'm talking about, you're only half right.

Not quite mate. Nothing to do with your knowledge of maths.

Just the two words 'mathematical' & 'beauty' look strange in the same sentence from my perspective; far from beauty IMO.