Find the value of x > 1 which satisfies the equation
x + x = x x .
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And it's pretty to guess that x is very small
Brilliant and simpleeee!!!
x + x = x x l o g ( x ) + l o g ( x ) = l o g ( x x ) 2 × l o g ( x ) = l o g ( x x ) 2 × l o g ( x ) = x × l o g ( x ) l o g ( x ) 2 × l o g ( x ) = x 2 = x
This is incorrect. Taking the log of both sides, you cannot split log(x+x) = log(x)+log(x)
If we rewrite that expression in x + x = 2 x , we have to satisfy the equation x x = 2 x . By definition, a exponential must have the following form: x x = x x x x x . . . , with all terms with the same value. So, with the condition x > 1 , the value of x must be equal to 2.
In this question, we have to use some trial and error method tricks. If we use some logic, we can certifying that number must be either 1or 2 because of they are the only options. Then by he equation we have to suggest the right answer.
If x is a real numbr , the answer is 2 . But if x is not a real numbr , the answer is 0..
0 is a real number and isn't a solution. because 0 0 isn't a real number
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Actually, X = 0 it is not a solution because does not satisfy X < 0 nor x^x = x + x
Wrong. 0 0 = 1 , and 1 is a real number. Because all real numbers to the zero power is by definition equal to 1. Therefore, isn't a solution for this problem.
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0^0 is undefined. The rule is a^0 =1 for all real a not equal to 0.
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@Julian Fuller – Please, read these links: Link 1 Link 2
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@Márcio Gomes – About those links you showed. Have a subtle conceptual mistakes. It's very interesting find them
That's completely wrong if you supose 0 0 is a real number you will get contradictions like 0 0 = 0 a − a = 0 a 0 a = 0 0 = ?
Here,
x+x= x^x
Then,
2x= x^x
Or,
x^x= 2x
x^(x-1)= 2^1
i.e. x^(x-1)= 2^(2-1)
Comparing we get,
x=2. RJ
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Here,
x+x= x^x
Then,
2x= x^x
Or,
x^x= 2x
x^(x-1)= 2^1
i.e. x^(x-1)= 2^(2-1)
Comparing we get,
x=2