Solving a logarithmic equation.
Solve each equation. Check your answers.
2 log x = -1
2 log ( x + 1 ) = 5
please explain!!!
Solve each equation. Check your answers.
2 log x = -1
2 log ( x + 1 ) = 5
please explain!!!
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2 logx = -1 <=> logx = -1/2 <=> x = 10^-1/2 <=> x = sqrt(10)/10
2 log(x+1) = 5 <=> log(x+1)=5/2 <=> x+1 = 10^(5/2) <=> x = 100sqrt(10) + 1
You should remember that, logx = y <=> x = 10^y
This is for logarithms that have number 10 as a base. Generally log(a)x = y <=> x = a^y
2 log(x+1) = 5 <=> log(x+1)=5/2 <=> x+1 = 10^(5/2) <=> x = 100sqrt(10) + 1
You should remember that, logx = y <=> x = 10^y
This is for logarithms that have number 10 as a base. Generally log(a)x = y <=> x = a^y
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What I do with this sort of problem is recall these facts
log 100 = 2
so
10^2 = 100
log 1000 = 3
so
10^3 = 1000
Remember that log means log to the base 10 and ln means log to base e.
So, we have
2 log x = - 1
log x = - 1/2 = - 0.5
x = 10 ^ (-0.5) = 1 / 10^0.5 = 1 / √10 = 0.316
For the the second one, we have
2 log (x + 1) = 5
log (x + 1) = 5/2 = 2.5
(x + 1) = 10^(2.5) = 316.23
x = 316.23 - 1 = 315.23
log 100 = 2
so
10^2 = 100
log 1000 = 3
so
10^3 = 1000
Remember that log means log to the base 10 and ln means log to base e.
So, we have
2 log x = - 1
log x = - 1/2 = - 0.5
x = 10 ^ (-0.5) = 1 / 10^0.5 = 1 / √10 = 0.316
For the the second one, we have
2 log (x + 1) = 5
log (x + 1) = 5/2 = 2.5
(x + 1) = 10^(2.5) = 316.23
x = 316.23 - 1 = 315.23
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2log x = -1
So log x = -1/2
But notice that the log function is gives the number required for the base to be raised in power to give the number 'logarithmised'. So x is 10^(-1/2), which is 1/sqrt(10).
2log x+1 = 5
So log x+1 = 5/2
so x+1 = 10^(5/2) = 100sqrt(10). so x is 100sqrt(10) - 1.
So log x = -1/2
But notice that the log function is gives the number required for the base to be raised in power to give the number 'logarithmised'. So x is 10^(-1/2), which is 1/sqrt(10).
2log x+1 = 5
So log x+1 = 5/2
so x+1 = 10^(5/2) = 100sqrt(10). so x is 100sqrt(10) - 1.