The maths thread

[JimC]

Here is a thread to either bring interesting tit-bits of mathematics, or to pose either challenge problems, or "Help me, my brain hurts" questions. On this computer, I dont have access to fancy maths equation writing software, but never mind.

Challenge 1

What must I multiply (root 7 + root 3) by to produce a rational number as an answer, and what will that rational number be?

[Chinaski]

I can't do Sine functions

[JimC]

I can't do Sine functions

Thats OK, it's not a Sine, it's all about surds!

(waits for the nervous giggles, just like my Yr 9 boys... )

[Chinaski]

I understand Trig, I got the Sine, Cosine and Tangent rules, but when it comes to radians, degrees and Sine functions... WTF????

[Xamonas Chegwé]

Here is a thread to either bring interesting tit-bits of mathematics, or to pose either challenge problems, or "Help me, my brain hurts" questions. On this computer, I dont have access to fancy maths equation writing software, but never mind.

Challenge 1

What must I multiply (root 7 + root 3) by to produce a rational number as an answer, and what will that rational number be?

0 and 0 respectively. Easy!

[Chinaski]

Dammit, should've known that.

[JimC]

Here is a thread to either bring interesting tit-bits of mathematics, or to pose either challenge problems, or "Help me, my brain hurts" questions. On this computer, I dont have access to fancy maths equation writing software, but never mind.

Challenge 1

What must I multiply (root 7 + root 3) by to produce a rational number as an answer, and what will that rational number be?

0 and 0 respectively. Easy!

Damnit, that's cheating!

(mind you, I should have specified "not zero")

There is indeed a simple, integer solution.

Think conjugates...

[Xamonas Chegwé]

Here is a thread to either bring interesting tit-bits of mathematics, or to pose either challenge problems, or "Help me, my brain hurts" questions. On this computer, I dont have access to fancy maths equation writing software, but never mind.

Challenge 1

What must I multiply (root 7 + root 3) by to produce a rational number as an answer, and what will that rational number be?

0 and 0 respectively. Easy!

Damnit, that's cheating!

(mind you, I should have specified "not zero")

There is indeed a simple, integer solution.

Think conjugates...

OK

One over (root 7 + root 3) - which of course gives the answer....






wait for it, this number is going to blow your tits into orbit!...


...





...




...



....




ONE!!



(but my answer was neater, rounder and had better tits!)

[JimC]

No, no, no...

The correct answer is that you multiply it by its conjugate (root 7 - root 3), and then, when you expand the brackets, = 3.

Pure magic!

[Xamonas Chegwé]

No, no, no...

The correct answer is that you multiply it by its conjugate (root 7 - root 3), and then, when you expand the brackets, = 3.

Pure magic!

err... if you're going to do it that way, don't you get 4? Just asking...

And (root 3 - root 7) would give you -4.

Next time can we have a question with just ONE right answer!



Try this one for a laugh. For what negative values of x does the function f(x) = x^x (that's x to the power x) have values that are: -
(a) Positive and real?
(b) Negative and real?
(c) Imaginary?
(d) Undefined?

There are infinite solutions but they can be expressed quite succinctly.

You can also try differentiating the function as well - not especially difficult but needs a little head-jugglery.

Answers after the Leeds meet up.

[JimC]

No, no, no...

The correct answer is that you multiply it by its conjugate (root 7 - root 3), and then, when you expand the brackets, = 3.

Pure magic!

err... if you're going to do it that way, don't you get 4? Just asking...

And (root 3 - root 7) would give you -4.

Next time can we have a question with just ONE right answer!



Try this one for a laugh. For what negative values of x does the function f(x) = x^x (that's x to the power x) have values that are: -
(a) Positive and real?
(b) Negative and real?
(c) Imaginary?
(d) Undefined?

There are infinite solutions but they can be expressed quite succinctly.

You can also try differentiating the function as well - not especially difficult but needs a little head-jugglery.

Answers after the Leeds meet up.

Damn! 7 - 3 indeed = 4 (I am a careless bugger at times!)

Will think about your problem, with pen & paper...

[atrasicarius]

No, no, no...

The correct answer is that you multiply it by its conjugate (root 7 - root 3), and then, when you expand the brackets, = 3.

Pure magic!

err... if you're going to do it that way, don't you get 4? Just asking...

And (root 3 - root 7) would give you -4.

Next time can we have a question with just ONE right answer!



Try this one for a laugh. For what negative values of x does the function f(x) = x^x (that's x to the power x) have values that are: -
(a) Positive and real?
(b) Negative and real?
(c) Imaginary?
(d) Undefined?

There are infinite solutions but they can be expressed quite succinctly.

You can also try differentiating the function as well - not especially difficult but needs a little head-jugglery.

Answers after the Leeds meet up.

a) x=-2n
b) x=-2n+1
c) x=-n+1/2
d) everything else

[The Curious Squid]

Thanks Jim

There's something really satisfying about solving maths problems, I'm afraid I'm more rusty than I expected though since my head is close to melting after reading the 11 posts on here so far.

I'm talking forgotten how to complete the square type rusty. You feel like getting me back on track coach?

[JimC]

Thanks Jim

There's something really satisfying about solving maths problems, I'm afraid I'm more rusty than I expected though since my head is close to melting after reading the 11 posts on here so far.

I'm talking forgotten how to complete the square type rusty. You feel like getting me back on track coach?

It's scary. These days, I just reach for my algebra-friendly, touch-screen calculator, type in any complicated equation, and press solve...

Soon, I may forget how to solve x + 2 = 5

[cowiz]

Soon, I may forget how to solve x + 2 = 5

I give up, what's the answer?