If x^2 = 1 then, x = -1, 1

In logarithm,

log(x^2) = log(1)

or, log((-1)^2) = 0

or, 2 * log(-1) = 0

so, log(-1) = 0

but we know that log(-1) is invalid. What is the problem in this equation??

If x^2 = 1 then, x = -1, 1

In logarithm,

log(x^2) = log(1)

or, log((-1)^2) = 0

or, 2 * log(-1) = 0

so, log(-1) = 0

but we know that log(-1) is invalid. What is the problem in this equation??

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TopNewestlog x^2=log 1 10^log 1=x^2 {using property a^logN(at base a)=N} 1=x^2 we are again at the same solution , x=(1,-1). But in the given proof you cannot use the value of x =-1 in the fourth step right like Trevor says. – Raven Herd · 3 years, 2 months ago

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Look at the reverse process: \(10^0=1≠-1\) – Trevor B. · 3 years, 5 months ago

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– Fahim Rahman · 3 years, 5 months ago

now how can i prove that x = -1 form that equation using logarithm?Log in to reply

The mistake is in the fourth line of the proof, where you say that the \(\sqrt{1}=-1.\) – Trevor B. · 3 years, 5 months ago

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