Problem

Simplify | square root of 11+i square root of 5|

The question is asking for you to find the absolute value (or magnitude) of a complex number which is given in the form √11 + i√5 where "i" represents the imaginary unit. The task is to simplify this expression to find the absolute value, which geometrically represents the distance of the complex number from the origin in the complex plane.

$\left|\right. \sqrt{11} + i \sqrt{5} \left|\right.$

Answer

Expert–verified

Solution:

Step:1 Switch the positions of $i$ and $\sqrt{5}$ to match the standard complex number format.$\left|\right. \sqrt{11} + i\sqrt{5} \left|\right.$

Step:2 Apply the modulus formula for a complex number $\left|\right. a + bi \left|\right. = \sqrt{a^{2} + b^{2}}$ to calculate the magnitude.$\sqrt{\left(\sqrt{11}\right)^{2} + \left(\sqrt{5}\right)^{2}}$

Step:3 Simplify $\left(\sqrt{11}\right)^{2}$ to $11$.

Step:3.1 Express $\sqrt{11}$ using exponent notation as $\left(11\right)^{\frac{1}{2}}$.$\sqrt{\left(\left(11\right)^{\frac{1}{2}}\right)^{2} + \left(\sqrt{5}\right)^{2}}$

Step:3.2 Utilize the exponent multiplication rule, which states $\left(a^{m}\right)^{n} = a^{m \cdot n}$.$\sqrt{11^{\frac{1}{2} \cdot 2} + \left(\sqrt{5}\right)^{2}}$

Step:3.3 Combine the exponents $\frac{1}{2}$ and $2$.$\sqrt{11^{\frac{2}{2}} + \left(\sqrt{5}\right)^{2}}$

Step:3.4 Eliminate the common factor of $2$.

Step:3.4.1 Remove the common factor from the exponent.$\sqrt{11^{\frac{\cancel{2}}{\cancel{2}}} + \left(\sqrt{5}\right)^{2}}$

Step:3.4.2 Rewrite the simplified expression.$\sqrt{11^{1} + \left(\sqrt{5}\right)^{2}}$

Step:3.5 Evaluate the exponent to its simplest form.$\sqrt{11 + \left(\sqrt{5}\right)^{2}}$

Step:4 Simplify $\left(\sqrt{5}\right)^{2}$ to $5$.

Step:4.1 Express $\sqrt{5}$ using exponent notation as $5^{\frac{1}{2}}$.$\sqrt{11 + \left(5^{\frac{1}{2}}\right)^{2}}$

Step:4.2 Apply the exponent multiplication rule.$\sqrt{11 + 5^{\frac{1}{2} \cdot 2}}$

Step:4.3 Combine the exponents $\frac{1}{2}$ and $2$.$\sqrt{11 + 5^{\frac{2}{2}}}$

Step:4.4 Eliminate the common factor of $2$.

Step:4.4.1 Remove the common factor from the exponent.$\sqrt{11 + 5^{\frac{\cancel{2}}{\cancel{2}}}}$

Step:4.4.2 Rewrite the simplified expression.$\sqrt{11 + 5^{1}}$

Step:4.5 Evaluate the exponent to its simplest form.$\sqrt{11 + 5}$

Step:5 Final simplification of the expression.

Step:5.1 Combine $11$ and $5$.$\sqrt{16}$

Step:5.2 Express $16$ as the square of $4$, which is $4^{2}$.$\sqrt{4^{2}}$

Step:5.3 Extract the square root of a perfect square, assuming positive real numbers.$4$

Knowledge Notes:

  1. Complex Numbers: A complex number is of the form $a + bi$ where $a$ is the real part, $b$ is the imaginary part, and $i$ is the imaginary unit with the property $i^2 = -1$.

  2. Modulus of a Complex Number: The modulus of a complex number $a + bi$ is given by $\sqrt{a^2 + b^2}$, representing the distance of the complex number from the origin in the complex plane.

  3. Exponent Rules: The power of a power rule states that $(a^m)^n = a^{m \cdot n}$. Also, $a^1 = a$ and $a^0 = 1$ for any non-zero $a$.

  4. Square Roots and Exponents: The square root of a number $a$ can be written as $a^{\frac{1}{2}}$. Squaring the square root of a number returns the original number, i.e., $(\sqrt{a})^2 = a$.

  5. Simplifying Expressions: The process of simplifying expressions involves applying arithmetic operations and algebraic rules to rewrite expressions in a simpler or more convenient form.

  6. Perfect Squares: A perfect square is a number that is the square of an integer. The square root of a perfect square is an integer. For example, $16$ is a perfect square because it is $4^2$, and its square root is $4$.

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