How does one solve $\log (2x - 1) = 3$ ?
Answer
622.2k+ views
Hint:For simplifying the original equation , take base ten exponential of both sides of the equation, then apply the logarithm formula ${b^{{{\log }_b}a}} = a$ to simplify the equation. Then recall that the logarithm function says $\log x$ is only defined when $x$ is greater than zero.
Formula used:
We used logarithm property i.e.
${b^{{{\log }_b}a}} = a$ , the logarithm function says $\log x$ is only defined when $x$ is greater than zero.
Complete solution step by step:
It is given that ,
$\log (2x - 1) = 3$
We have to solve for $x$ ,
Now , by assuming the base of the logarithm to be $10$ ,then take the base $10$ exponential of both sides of the equation, we will get the following result ,
${10^{{{\log }_{10}}(2x - 1)}} = {10^3}$
By applying the logarithm formula ${b^{{{\log }_b}a}} = a$ . we will get the following result ,
$2x - 1 = 1000$ ,
Now simplify the above equation as ,
$
\Rightarrow 2x = 1000 + 1 \\
\Rightarrow 2x = 1001 \\
\Rightarrow x = \dfrac{{1001}}{2} \\
$
Now recall that the logarithm function says $\log x$ is only defined when $x$ is greater than zero.
Therefore, in our original equation $\log (2x - 1) = 3$ ,
Here we must have ,
$(2x - 1) > 0$ ,
We have $x = \dfrac{{1001}}{2}$
We get ,
$1000 > 0$
Therefore, we have our solution i.e., $x = \dfrac{{1001}}{2}$ .
Note: The logarithm function says $\log x$ is only defined when $x$ is greater than zero. While defining logarithm function one should remember that the base of the log must be a positive real number and not equals to one . At the end we must recall that the logarithm function says $\log x$ is only defined when $x$ is greater than zero. While performing logarithm properties we have remember certain conditions , our end result must satisfy domain of that logarithm
Formula used:
We used logarithm property i.e.
${b^{{{\log }_b}a}} = a$ , the logarithm function says $\log x$ is only defined when $x$ is greater than zero.
Complete solution step by step:
It is given that ,
$\log (2x - 1) = 3$
We have to solve for $x$ ,
Now , by assuming the base of the logarithm to be $10$ ,then take the base $10$ exponential of both sides of the equation, we will get the following result ,
${10^{{{\log }_{10}}(2x - 1)}} = {10^3}$
By applying the logarithm formula ${b^{{{\log }_b}a}} = a$ . we will get the following result ,
$2x - 1 = 1000$ ,
Now simplify the above equation as ,
$
\Rightarrow 2x = 1000 + 1 \\
\Rightarrow 2x = 1001 \\
\Rightarrow x = \dfrac{{1001}}{2} \\
$
Now recall that the logarithm function says $\log x$ is only defined when $x$ is greater than zero.
Therefore, in our original equation $\log (2x - 1) = 3$ ,
Here we must have ,
$(2x - 1) > 0$ ,
We have $x = \dfrac{{1001}}{2}$
We get ,
$1000 > 0$
Therefore, we have our solution i.e., $x = \dfrac{{1001}}{2}$ .
Note: The logarithm function says $\log x$ is only defined when $x$ is greater than zero. While defining logarithm function one should remember that the base of the log must be a positive real number and not equals to one . At the end we must recall that the logarithm function says $\log x$ is only defined when $x$ is greater than zero. While performing logarithm properties we have remember certain conditions , our end result must satisfy domain of that logarithm
Recently Updated Pages
Write structures of the following compounds i 2 Chloro3methylpentane class 11 chemistry CBSE

What is BLO What is the full form of BLO class 8 social science CBSE

Explain the Treaty of Vienna of 1815 class 10 social science CBSE

A Paragraph on Pollution in about 100-150 Words

XIX+XXX A 49 B 51 C 55 D 44 class 5 maths CBSE

If x a + bt + ct2 where x is in meters and t is in class 11 physics CBSE

Trending doubts
One Metric ton is equal to kg A 10000 B 1000 C 100 class 11 physics CBSE

Draw a diagram of nephron and explain its structur class 11 biology CBSE

10 examples of friction in our daily life

Proton was discovered by A Thomson B Rutherford C Chadwick class 11 chemistry CBSE

Bond order ofO2 O2+ O2 and O22 is in order A O2 langle class 11 chemistry CBSE

Draw a labelled diagram of the neuron and describe class 11 biology CBSE

