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Mathematics 7 Online
OpenStudy (faiqraees):

@ganeshie8

OpenStudy (faiqraees):

Prove using induction that x+3=5x for all real values of x. (This is a question I made up just to see how are we suppose to use induction upon false statements)

ganeshie8 (ganeshie8):

It is not possible to prove a false statement using induction or any other proof method. You would fail if you tried.

OpenStudy (faiqraees):

Yeah I know, I just want to see how is the question going to be disproved

ganeshie8 (ganeshie8):

You may simply show a counterexample.

OpenStudy (faiqraees):

But still I want to know how induction proofing workouts on false statement. (Like what if a statement is there for which I cant work out the authenticity of the statement

OpenStudy (faiqraees):

Like first we will assume x+3=5x to be true and then we can check for this assumption by using x = 3/4. Then I will try to show the statement (x+1)+3=5(x+1) to be true by making algebraic manipulation in our hypothesis. Right?

ganeshie8 (ganeshie8):

We must have a high confidence about the validity of the proposition before applying induction.

OpenStudy (faiqraees):

What if they just say determine p=>q is true or false? (which coincidentally works out for all real values of x except 1,2 special values). What method am I supposed to adopt here?

ganeshie8 (ganeshie8):

Also the usual induction method doesn't work on real numbers

OpenStudy (faiqraees):

Why not?

ganeshie8 (ganeshie8):

Have you gone through the proof of induction method ?

OpenStudy (faiqraees):

Yes, even applied sometimes

ganeshie8 (ganeshie8):

The simplest and most common form of mathematical induction infers that a statement involving a natural number n holds for all values of n. https://en.wikipedia.org/wiki/Mathematical_induction

OpenStudy (faiqraees):

Oh but still that doesn't answer my question. What if they just say determine p=>q is true or false? (which coincidentally works out for all natural values of x except 1,2 special values). What method am I supposed to adopt here?

ganeshie8 (ganeshie8):

Your question isn't clear. What are p and q ?

OpenStudy (faiqraees):

They are just statements

ganeshie8 (ganeshie8):

You're free to adopt any method as long as you know how to follow the rules

OpenStudy (faiqraees):

Oh okay. Can you just check my working for a question of proof?

ganeshie8 (ganeshie8):

Sure..

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