Tilted Forum Project Discussion Community

Tilted Forum Project Discussion Community (https://thetfp.com/tfp/)
-   Tilted Knowledge and How-To (https://thetfp.com/tfp/tilted-knowledge-how/)
-   -   Why does a number raised to the zero = 1? (https://thetfp.com/tfp/tilted-knowledge-how/57944-why-does-number-raised-zero-1-a.html)

Slavakion 06-04-2004 01:38 PM

Why does a number raised to the zero = 1?
 
Is there an actual mathematical proof as to why a number raised to the 0th power equals one? Today in our physics class, someone said that she asked the math teacher, who said that it just does. The physics teacher couldn't explain it, and made a wild stab at it.

10^3 = 10*10*10
10^2 = 10*10
10^1 = 10*1
10^0 = 10*.1

It was a good effort, but it only works for ten. Any ideas?

irseg 06-04-2004 01:57 PM

Interesting question. I did a quick search on Google, and found:

http://mathforum.org/dr.math/faq/faq...to.0power.html

spived2 06-04-2004 02:13 PM

3^4
1 = ----- = 3^(4-4) = 3^0
3^4


This equation pretty much sums it up. Good find irseg

Yakk 06-04-2004 02:28 PM

Lets start with x^a

What happens when you take x^a * x^b?

You get x^(a+b), if a and b are positive integers.

Hmm. So, what should x^0 be? Well, that's a nice rule. Can we make it true for x^0 as well as other positive integers?

x^a * x^0 = x^(a+0) for all a and x
x^a * x^0 = x^a for all a and x
x^0 = 1 for all x for which x^a does not equal zero

So, if x is not zero, if you want the x^a*x^b = x^(a+b) rule to work for x^0, x^0 must be zero.

The same lets you work out what happens with negative numbers: you get x^-a = 1/x^a

This is how you get many rules in mathematics: you take the basic definition for positive integers, find a nice property, and extend it to all integers, or even all real numbers, in such a way that the nice property still holds.

Slavakion 06-04-2004 06:51 PM

awesomeness. I'll probably use yours in class monday, Yakk. Only because it looks more like the traditional proofs.

rsl12 06-05-2004 09:03 PM

Consider the limit of y=2^x, where x is a number very very close to 0 but not quite, such as one thousandth (1/1000). In other words, y is equal to some number that you would have to multiply a thousand times with itself in order to get the number 2. Obviously y would have to be really close to 1 in order for this to happen. Consider if x = one millionth. one over a googol. you get the idea.

rsl12 06-05-2004 09:06 PM

i dunno what level math your are in, but if you want to do it right, the limit argument is only convincing if also consider the limit from the other side as well (ie, negative #s very very close to 0). The same logic applies.

Yakk 06-07-2004 05:50 AM

RSL, how was it decided that
x^(1/100) = 100th root of x

They took the arithmetically true statements (x^a*x^b = x^(a+b), (x^a)^b = x^a*b, etc, where x^a = x*x*..*x (a times)), and extended them to the rationals, then the reals.

x^(1/2) = square root of x
because
x^(1/2) * x^(1/2) = x^(1/2+1/2) = x
the non-rational reals are then defined by making the function continuous (which also, independantly, results in x^0 = 1 for all x not equal to zero).

Interestingly, f(x,a) := x^a is not continuous everywhere: f(0,a) either has a discontinuity at a=0, or f(x,0) has a discontinuity at x=0. Hence the 0^0 problem.

rsl12 06-07-2004 02:55 PM

yup yakk, i wonder if ever there will be a new set of numbers (like imaginary numbers) based on 0^0...

your explanation is more rigid. mine, i'd like to think, is more common sense. I'm an engineer, not a mathematician.

llama8 06-07-2004 03:29 PM

I always remember being told by my maths lecturer that it is true because "all the equations work when it is true".

Hardly a rigorous proof but there you go!

Grothendieck 06-16-2004 01:53 AM

That x^0=1 is a convention which makes formulae nicer. There is no "proof" of it. For instance, sometimes it is more useful to set 0^0=0. The philosophy is that 1 is the neutral element for multiplication, so if we multiply nothing (i.e. ^0), we stay with the neutral element. Much as if we add nothing, we get 0, the neutral element for addition.

MoJoPokeyBlue 06-28-2004 12:59 PM

You're absolutely right...there's no good reason why a number raised to the 0th power equals one!

I hereby decree, that from this day forward, all numbers raised to the 0th power equal 3.

Who's with me?

Tempboy 06-29-2004 05:57 AM

Yikes, those all look overly complicated up there..

If I recall my old high school math, this is how it was taught to me:

Let's take x squared for a simple example: x^2

(x^2) / (x^2)

To solve this, we would subtract the exponents...so 2-2=0
We end up with:
x^0

Also, with basic math we know that any number divided by itself equals 1.

Therefore we end up with:
(x^2) / (x^2) = x^0
(x^2) / (x^2) = 1

And so:
x^0 = 1


All times are GMT -8. The time now is 11:47 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
© 2002-2012 Tilted Forum Project


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360