Find the square root of\[x + i\sqrt {{x^4} + {x^2} + 1} \]where\[i = \sqrt { - 1} \].
Answer
663k+ views
Hint: The square root of a number is raising the number to the power of 0.5, such as${a^{\left( {\dfrac{1}{2}} \right)}}$. This can also be denoted as $\sqrt a $ and is abbreviated as the square root of$a$. A complex number is a combination of real and imaginary parts and is denoted as$z = a + ib$. To find the square root of a complex number, equate the given equation with the standard complex number \[z = a + ib\] where \[a\] and \[b\] are real part and imaginary part, respectively, \[i\]being an imaginary unit that is mathematically defined as $i = \sqrt { - 1} $. Then, square both sides of the resulting equation and compare the real and imaginary parts of the equations to determine the coefficients.
Complete step by step answer:
Let, \[\sqrt {x + i\sqrt {{x^4} + {x^2} + 1} } = a + ib\]
Squaring both the sides we get,
\[
\sqrt {x + i\sqrt {{x^4} + {x^2} + 1} } = a + ib \\
{\left( {\sqrt {x + i\sqrt {{x^4} + {x^2} + 1} } } \right)^2} = {\left( {a + ib} \right)^2} \\
\]
Here in the first term we can cancel square and the square root and for the second term we have to apply ${(a+b)^2}$ formula, then we will get
\[
x + i\sqrt {{x^4} + {x^2} + 1} = {a^2} + {\left( {ib} \right)^2} + 2iab \\
x + i\sqrt {{x^4} + {x^2} + 1} = {a^2} + \left( {{{\left( {\sqrt { - 1} } \right)}^2}{b^2}} \right) + i2ab \\
x + i\sqrt {{x^4} + {x^2} + 1} = \left( {{a^2} - {b^2}} \right) + i\left( {2ab} \right) \\
\]
Now, comparing both sides of the real & imaginary parts, we get
\[({a^2} - {b^2}) = x\] -- (i) And, \[2ab = \sqrt {{x^4} + {x^2} + 1} \] --(ii)
Squaring above equations (i) and (ii), equations can be written as
\[{({a^2} - {b^2})^2} = {x^2}\] And, \[4{a^2}{b^2} = {x^4} + {x^2} + 1\]
We can write \[{({a^2} + {b^2})^2}\] as:
\[
{({a^2} + {b^2})^2} = {({a^2} - {b^2})^2} + 4{a^2}{b^2} \\
= \left( {{x^2}} \right) + \left( {{x^4} + {x^2} + 1} \right) \\
= {x^4} + 2{x^2} + 1 \\
= {({x^2} + 1)^2} \\
\sqrt {{{\left( {{a^2} + {b^2}} \right)}^2}} = \sqrt {{{\left( {{x^2} + 1} \right)}^2}} \\
\left( {{a^2} + {b^2}} \right) = \left( {{x^2} + 1} \right) \\
\]
We get \[{a^2} + {b^2} = {x^2} + 1\]-- (iii)
Now, solving the equations by adding (i) and (iii) to find the real term \[a\]of the equation we have,
\[
{a^2} - {b^2} + {a^2} + {b^2} = {x^2} + x + 1 \\
2{a^2} = {x^2} + x + 1 \\
{a^2} = \dfrac{{{x^2} + x + 1}}{2} \\
\]
Or, \[a = \sqrt {\dfrac{{{x^2} + x + 1}}{2}} \]
Now for the imaginary term\[b\], subtract equation (i) from (iii) we get:
\[
{a^2} + {b^2} - {a^2} + {b^2} = {x^2} + 1 - x \\
2{b^2} = {x^2} - x + 1 \\
{b^2} = \dfrac{{{x^2} - x + 1}}{2} \\
b = \sqrt {\dfrac{{{x^2} - x + 1}}{2}} \\
\]
Hence we have, \[\sqrt {x - i\sqrt {{x^4} + {x^2} + 1} } \]\[ = \sqrt {\dfrac{{{x^2} + x + 1}}{2}} \]\[ + i\sqrt {\dfrac{{{x^2} - x + 1}}{2}} \]
Note: In general, when we have to find an imaginary term in the given equation, we need to equate the equation with the complex equation\[z = a + ib\], where \[a\]is the real term and \[b\]imaginary term and then carryout the general process of squaring, comparing and solving the resulting equations. Complex equations generally denote imaginary parts of the complex equations.
Complete step by step answer:
Let, \[\sqrt {x + i\sqrt {{x^4} + {x^2} + 1} } = a + ib\]
Squaring both the sides we get,
\[
\sqrt {x + i\sqrt {{x^4} + {x^2} + 1} } = a + ib \\
{\left( {\sqrt {x + i\sqrt {{x^4} + {x^2} + 1} } } \right)^2} = {\left( {a + ib} \right)^2} \\
\]
Here in the first term we can cancel square and the square root and for the second term we have to apply ${(a+b)^2}$ formula, then we will get
\[
x + i\sqrt {{x^4} + {x^2} + 1} = {a^2} + {\left( {ib} \right)^2} + 2iab \\
x + i\sqrt {{x^4} + {x^2} + 1} = {a^2} + \left( {{{\left( {\sqrt { - 1} } \right)}^2}{b^2}} \right) + i2ab \\
x + i\sqrt {{x^4} + {x^2} + 1} = \left( {{a^2} - {b^2}} \right) + i\left( {2ab} \right) \\
\]
Now, comparing both sides of the real & imaginary parts, we get
\[({a^2} - {b^2}) = x\] -- (i) And, \[2ab = \sqrt {{x^4} + {x^2} + 1} \] --(ii)
Squaring above equations (i) and (ii), equations can be written as
\[{({a^2} - {b^2})^2} = {x^2}\] And, \[4{a^2}{b^2} = {x^4} + {x^2} + 1\]
We can write \[{({a^2} + {b^2})^2}\] as:
\[
{({a^2} + {b^2})^2} = {({a^2} - {b^2})^2} + 4{a^2}{b^2} \\
= \left( {{x^2}} \right) + \left( {{x^4} + {x^2} + 1} \right) \\
= {x^4} + 2{x^2} + 1 \\
= {({x^2} + 1)^2} \\
\sqrt {{{\left( {{a^2} + {b^2}} \right)}^2}} = \sqrt {{{\left( {{x^2} + 1} \right)}^2}} \\
\left( {{a^2} + {b^2}} \right) = \left( {{x^2} + 1} \right) \\
\]
We get \[{a^2} + {b^2} = {x^2} + 1\]-- (iii)
Now, solving the equations by adding (i) and (iii) to find the real term \[a\]of the equation we have,
\[
{a^2} - {b^2} + {a^2} + {b^2} = {x^2} + x + 1 \\
2{a^2} = {x^2} + x + 1 \\
{a^2} = \dfrac{{{x^2} + x + 1}}{2} \\
\]
Or, \[a = \sqrt {\dfrac{{{x^2} + x + 1}}{2}} \]
Now for the imaginary term\[b\], subtract equation (i) from (iii) we get:
\[
{a^2} + {b^2} - {a^2} + {b^2} = {x^2} + 1 - x \\
2{b^2} = {x^2} - x + 1 \\
{b^2} = \dfrac{{{x^2} - x + 1}}{2} \\
b = \sqrt {\dfrac{{{x^2} - x + 1}}{2}} \\
\]
Hence we have, \[\sqrt {x - i\sqrt {{x^4} + {x^2} + 1} } \]\[ = \sqrt {\dfrac{{{x^2} + x + 1}}{2}} \]\[ + i\sqrt {\dfrac{{{x^2} - x + 1}}{2}} \]
Note: In general, when we have to find an imaginary term in the given equation, we need to equate the equation with the complex equation\[z = a + ib\], where \[a\]is the real term and \[b\]imaginary term and then carryout the general process of squaring, comparing and solving the resulting equations. Complex equations generally denote imaginary parts of the complex equations.
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

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

What do you mean by retardation What is its SI uni 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

Difference between physical and chemical change class 11 chemistry CBSE

