Question:

If $z=\frac{7-i}{3-4i} \, then\, z^{14}=$

Updated On: Aug 15, 2024
  • $2^{7}$
  • $2^{7} i$
  • $2^{14} i$
  • $-2^{7}i$
Hide Solution
collegedunia
Verified By Collegedunia

The Correct Option is D

Solution and Explanation

$z=\frac{7- i}{3-4 i} \times\frac{3+4i}{3+4i}$
$=\frac{21+25 i+4}{16+9}=\frac{25\left(1+i\right)}{25}=\left(1+i\right)$
$z^{14}=\left(1+i\right)^{14}=\left[\left(1+i\right)^{2}\right]^{7}=\left(2i\right)^{7}=2^{7} i^{7}=-2^{7} i$
Was this answer helpful?
1
0

Concepts Used:

Quadratic Equations

A polynomial that has two roots or is of degree 2 is called a quadratic equation. The general form of a quadratic equation is y=ax²+bx+c. Here a≠0, b, and c are the real numbers

Consider the following equation ax²+bx+c=0, where a≠0 and a, b, and c are real coefficients.

The solution of a quadratic equation can be found using the formula, x=((-b±√(b²-4ac))/2a)

Two important points to keep in mind are:

  • A polynomial equation has at least one root.
  • A polynomial equation of degree ‘n’ has ‘n’ roots.

Read More: Nature of Roots of Quadratic Equation

There are basically four methods of solving quadratic equations. They are:

  1. Factoring
  2. Completing the square
  3. Using Quadratic Formula
  4. Taking the square root