Solve the system -x - 2y = -11 and 9x + 8y = 19 by combining the equations

Assume z = x + iy, then find a complex number z satisfying the given equation. d. 2z8 – 2z4 + 1 = 0

kodGreya [7K]

Answer: complex equations has n number of solutions, been n the equation degree. In this case:

$Z=\frac{\sqrt[8]{2} }{\sqrt[4]{2}} e^{i11,25°}$

$Z=\frac{\sqrt[8]{2} }{\sqrt[4]{2}} e^{i101,25°}$

$Z=\frac{\sqrt[8]{2} }{\sqrt[4]{2}} e^{i191,25°}$

$Z=\frac{\sqrt[8]{2} }{\sqrt[4]{2}} e^{i281,25°}$

$Z=\frac{\sqrt[8]{2} }{\sqrt[4]{2}} e^{i78,75°}$

$Z=\frac{\sqrt[8]{2} }{\sqrt[4]{2}} e^{i168,75°}$

$Z=\frac{\sqrt[8]{2} }{\sqrt[4]{2}} e^{i258,75°}$

$Z=\frac{\sqrt[8]{2} }{\sqrt[4]{2}} e^{i348,75°}$

Step-by-step explanation:

I start with a variable substitution:

$Z^{4} = X$

Then:

$2X^{2}-2X+1=0$

Solving the quadratic equation:

$X_{1} =\frac{2+\sqrt{4-4*2*1} }{2*2} \\X_{2} =\frac{2-\sqrt{4-4*2*1} }{2*2}$

$X=\left \{ {{0,5+0,5i} \atop {0,5-0,5i}} \right.$

Replacing for the original variable:

$Z=\sqrt[4]{0,5+0,5i}$

or $Z=\sqrt[4]{0,5-0,5i}$

Remembering that complex numbers can be written as:

$Z=a+ib=|Z|e^{ic}$

Using this:

$Z=\left \{ {{{\frac{\sqrt{2}}{2} e^{i45°} } \atop {{\frac{\sqrt{2}}{2} e^{i-45°} }} \right.$

Solving for the modulus and the angle:

$Z=\left \{ {{\sqrt[4]{\frac{\sqrt{2}}{2} e^{i45}} = \sqrt[4]{\frac{\sqrt{2}}{2} } \sqrt[4]{e^{i45}} } \atop {\sqrt[4]{\frac{\sqrt{2}}{2} e^{i-45}} = \sqrt[4]{\frac{\sqrt{2}}{2} } \sqrt[4]{e^{i-45}} }} \right.$

The possible angle respond to:

$RAng_{12...n} =\frac{Ang +360*(i-1)}{n}$

Been "RAng" the resultant angle, "Ang" the original angle, "n" the degree of the root and "i" a value between 1 and "n"

In this case n=4 with 2 different angles: Ang = 45º and Ang = 315º

Obtaining 8 different angles, therefore 8 different solutions.

3 0

2 years ago

PLEASE HELP! PLEASE!!!!!!!

Sloan [31]

Using the equation of the proportional relationship:

Average rate of speed = 60

Time taken to go 300 miles = 5 hrs

Distance travelled in 2.5 hrs = 150 miles

<h3>What is a Equation of a Proportional Relationship?</h3>

A equation of a proportional relationship models the relationship between two variables, x and y, that has a constant of k. It is expressed as y = kx.

Given the following:

Equation: d = 60t

d = distance in miles

t = time in hours

Average rate of speed for the bus = k = 60

Time (t) it would take to go 300 miles (d):

300 = 60(t)

300/60 = t

t = 5 hours

Distance (d) it would travel in 2.5 hours (t):

d = 60(2.5)

d = 150 miles

Learn more about the equation of a proportional relationship on:

brainly.com/question/6869319

#SPJ1

8 0

2 years ago

Please help me

madreJ [45]

143.44 degrees
Hope this helps (:

7 0

1 year ago

In the first few weeks of the season, a basketball player averaged 27 points per game. Then the player was on a streak. The tab

vovikov84 [41]

Answer:

1.5

Step-by-step explanation:

3 0

2 years ago

Read 2 more answers

Solve using standard algorithm 57.03+2.08

Rom4ik [11]

Answer:

59.08

Step-by-step explanation:

6 0

2 years ago

Solve the system -x - 2y = -11 and 9x + 8y = 19 by combining the equations​

Solve the system -x - 2y = -11 and 9x + 8y = 19 by combining the equations