How do you solve \[{e^{2x + 1}} = 27\] ?
Answer
618.9k+ views
Hint: To solve the given equation, take natural logarithm on both the sides of the equation to remove the variable from the exponent, as Logarithmic functions are the inverses of exponential functions hence by this, we can get the value of \[x\].
Complete step by step solution:
Let us write the given equation
\[{e^{2x + 1}} = 27\]…………………….. 1
To solve this equation, take natural logarithm on both the sides of the equation 1 i.e.,
\[\ln \left( {{e^{2x + 1}}} \right) = \ln \left( {27} \right)\] ……………………… 2
Expand the LHS part by moving \[2x + 1\] outside the logarithm of equation 2, hence we get
\[2x + 1\ln \left( e \right) = \ln \left( {27} \right)\]
As we know the logarithm of function ‘\[e\]’ is 1, hence substituting this value in above equation
\[2x + 1\left( 1 \right) = \ln \left( {27} \right)\]
Which implies
\[2x + 1 = \ln \left( {27} \right)\] ………………………. 3
In which the value of \[\ln \left( e \right)\]= 1.
Equation 3 can be written as
\[2x + 1 = \ln {3^3}\]
\[2x + 1 = 3\ln 3\] ………………………… 4
As we need to find the value of \[x\], simplifying the terms of equation 4 we get
\[x = \dfrac{1}{2}\left( {3.\ln 3 - 1} \right)\]
Additional information:
Rules of Logarithms:
The logarithm of a positive real number can be negative, zero or positive.
Logarithmic values of a given number are different for different bases.
Logarithms to the base a 10 are referred to as common logarithms. When a logarithm is written without a subscript base, we assume the base to be 10.
Logarithms to the base ‘e’ are called natural logarithms. The constant e is approximated as 2.7183.
Natural logarithms are expressed as ln x which is the same as log e.
Note: The key point to find the given equation is that when the equation consists of exponential terms, just take natural logarithm on both the sides of the equation as to solve for the value of \[x\] we need to remove the variable from the exponent by taking ln of the function. As Logarithmic functions are the inverses of exponential functions.
Complete step by step solution:
Let us write the given equation
\[{e^{2x + 1}} = 27\]…………………….. 1
To solve this equation, take natural logarithm on both the sides of the equation 1 i.e.,
\[\ln \left( {{e^{2x + 1}}} \right) = \ln \left( {27} \right)\] ……………………… 2
Expand the LHS part by moving \[2x + 1\] outside the logarithm of equation 2, hence we get
\[2x + 1\ln \left( e \right) = \ln \left( {27} \right)\]
As we know the logarithm of function ‘\[e\]’ is 1, hence substituting this value in above equation
\[2x + 1\left( 1 \right) = \ln \left( {27} \right)\]
Which implies
\[2x + 1 = \ln \left( {27} \right)\] ………………………. 3
In which the value of \[\ln \left( e \right)\]= 1.
Equation 3 can be written as
\[2x + 1 = \ln {3^3}\]
\[2x + 1 = 3\ln 3\] ………………………… 4
As we need to find the value of \[x\], simplifying the terms of equation 4 we get
\[x = \dfrac{1}{2}\left( {3.\ln 3 - 1} \right)\]
Additional information:
Rules of Logarithms:
The logarithm of a positive real number can be negative, zero or positive.
Logarithmic values of a given number are different for different bases.
Logarithms to the base a 10 are referred to as common logarithms. When a logarithm is written without a subscript base, we assume the base to be 10.
Logarithms to the base ‘e’ are called natural logarithms. The constant e is approximated as 2.7183.
Natural logarithms are expressed as ln x which is the same as log e.
Note: The key point to find the given equation is that when the equation consists of exponential terms, just take natural logarithm on both the sides of the equation as to solve for the value of \[x\] we need to remove the variable from the exponent by taking ln of the function. As Logarithmic functions are the inverses of exponential functions.
Recently Updated Pages
If x a + bt + ct2 where x is in meters and t is in class 11 physics CBSE

A car covers the first half distance between two places class 11 physics CBSE

The resultant of two vectors overrightarrow P and overrightarrow class 11 physics CBSE

Find the value of cos 135 class 11 maths CBSE

A mass M is held in place by an applied force F and class 11 physics CBSE

A solution of glucose in water is labelled as 10 dfracwv class 11 chemistry CBSE

Trending doubts
Find the value of the expression given below sin 30circ class 11 maths CBSE

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

