MattMayD

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UsernameMattMayD
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 #2
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That, my friend, is one beautiful question and I will try to answer it as best as I can in as few words as possible but as many as needed for you to 'truly' (your words) get the idea.

 

Our universe is a funny place. Apparently there are some things which just are the way they are and nothing we could ever do will change that. Mathematics is basically the motherload of unchangable consistency in the universe. Everything you'll ever do will be limited by the boundries of the material representation of mathematical systems known as physics.

Pi is an extremely elegant and easy to understand example of that. Pi, of course, has something to do with circles. Now, circles don't exactly exist in the 'real' world and what i mean by that is that there isn't a physical representation of a one-dimensional point or a one-dimensional distance on a two-dimensional plane by which the circle is defined. So really when we say circle in mathematics what we mean by that is a two-dimensional structure which consists of a center represented by any one-dimensional point you can imagine and all the points that have a certain fixed distance from that center-point. What's funny about all that is that you can arbitrarily choose any point you want and any distance from that center-point to 'build' a circle and even tho you can do this as often as you want and with as many different values and positions there's one property which you have no influence over and that, my friend, is the ratio between the diameter (or twice the radius) and the circumference of a circle, which is what pi is. Pi is an unchangable ratio a so called 'constant'.

Sep 15, 2016
 #1
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Sep 15, 2016
 #1
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0

There's a simple answer to this and a fairly complicated one. I'll hint you the hard one in a short manner and give you the easy one. If you wanna understand the hard one answer to this post. It's quite tricky if you wanna do it by hand every time (involves writing the two points where the secant intersects with your function as (x/f(x)) and ((x+h)/f(x)) (h simply stands for a value that makes sure x and x+h are not the same). But there's an easier way. Unluckily this involves you believing me that what i tell you is true and kinda ruins the whole point of mathematics but whatever here it goes: There's a way of deriving a formula for any function so that what you get is actually the gradient in any point you choose on the original function. You do this by taking your function and lowering the exponent of every term in that function by '1' and putting the number it was in front of the term as a factor to the term. Maybe not the easiest thing to put in words so here's an example:

 

Modifying x^2 with this method you get 2*x^1 = 2x

3x^4 + x^2 + 7 becomes 4*3x^3 + 2*x (the 7 dissapears since it had exponent '1' and you're lowering that to '0')

 

The functions you get out of this are the gradients for the secants approaching lenght 0 you talked about in any point 'x' chosen by you.

 

Example: f(x) = x^2 , f'(x)=2*x

 

So the function x^2 has the gradient 2*x in point 'x' of the function x^2. This means that if you want to know the gradient in the point, say 4, you have to put '4' in the f'(x) function which is 2*4 = 8.

 

Hope i could help

 

Greetings

 

MayD

Sep 15, 2016