Simple maths problem?

[PaulStat]

Ok now this isn't for a course i'm doing, just "leisure" so no you're not doing my homework for me. Never the less it's bugging me.

The exercise is to do with using a calculator, to progress through a sequence of numbers for example the sequence

-1 1 3 5....

can be entered into the calculator like so

-1 enter + 2 enter enter enter......

Easy no? Ok so how about this sequence

4 0.25 4 0.25 4.....

Now i've figured out that 4/16=0.25 and 0.25*16=4, but the problem is this can't be entered into the calculator using the same method.

It's been at least 8 years since i've done anything like this!

 

[JIM_BOB7813]

^(-1)

 

[PaulStat]

^(-1)

Ok, but how did you figure that out

 

[Munkeh]

Just by inspection. One is the inverse of the next...

 

[PaulStat]

Just by inspection. One is the inverse of the next...

and ^(-1) is always the inverse?

 

[Psyk]

and ^(-1) is always the inverse?

x^-1 is the exact same as 1/x. You're raising the number to the power of -1 which is the same as dividing one by the number.

 

[Munkeh]

x^-1 is the exact same as 1/x. You're raising the number to the power of -1 which is the same as dividing one by the number.

Exactly, if your calculator has a 1/x button (inverse button) you could just use that instead.

 

[neil3k]

This confuses me.

 

[PaulStat]

Hmmm this will be why I got a D in A-Level maths

 

[chiggz]

i dont get why a calculator is involved.

can some hi-tech ones predict sequences or something? :S

edit: nvm, think i get it.. you wanted a constant 'function' that could be typed into a calculator to produce the next number (correct me if wrong).

 

[Lamo]

???

 

[gumbald]

???

 

[shauncr91]

This confuses me.

Same here, and the fact that it was labelled as 'simple' just makes me feel depressed

 

[gumbald]

It's two numbers, each is the inverse of the other, therefore can be reached in one step...

 

[mrmoose]

any more? I love these things.

 

[GarethDW]

This confuses me.

Same here.

 

[mrmoose]

x^-1 is the same as 1/x

4^-1 is the same as 1/4 which = 0.25

0.25^-1 is the same as 1/0.25 which is 4

can't see how this can trouble people really?

 

[BullBoyShoes]

the question doesnt even make sense

 

[p4radox]

the question doesnt even make sense

It makes perfect sense. He even gave you the sequence of keys needed to get the pattern.

 

[fred_easey]

So maybe the answer is

0.25 1/x 1/x =

And then each time you press equals it alternates between 0.25 and 4.

I've not got a calculator here though so can't check to see whether this is right or not.