True or False?

10\frac1001​ is undefined .

Why some people say it’s true: Dividing by 0 00 is not allowed .
Why some people say it’s false: 10=∞.\frac10 = \infty.01​=∞.

Can you see which of these is the adjust explanation ?

There are some coarse responses to this logic, but they all have versatile flaws .

See the consequences of assuming that 10\frac { 1 } { 0 } 01​ is defined for yourself in the watch problem :

Incorrect factoring

Multiplying unknown variables

False substitution

Introducing

−b2-b^2

b

2

Dividing by zero

What is ill-timed with the following “ proof ” ?
Let a=b=1a = b=1a=b=1, then a+b=b.a+b=b.a+b=b .

  • Step 1:

    a2=aba^2 = ab

    a

    2

    =

    a

    b

  • Step 2:

    a2−b2=ab−b2a^2 – b^2 = ab – b^2

    a

    2

    b

    2

    =

    a

    b

    b

    2

  • Step 3:

    (a+b)(a−b)=b(a−b)(a+b)(a-b) = b(a-b)

    (

    a

    +

    b

    )

    (

    a

    b

    )

    =

    b

    (

    a

    b

    )

  • Step 4:

    a+b=b(a−b)a−ba+b= \dfrac{b(a-b)}{a-b}

    a

    +

    b

    =

    a

    b

    b

    (

    a

    b

    )

  • Step 5:

    a+b=ba+b = b

    a

    +

    b

    =

    b

decision : By substituting in a=b=1, a = b = 1, a=b=1, we have 1+1=1 ⟹ 2=1.1+1 = 1 \implies 2 = 1.1+1=1⟹2=1 .
See Also