$\rightarrow z^4=-625\\\\\rightarrow z=(-625+0i)^{\frac{1}{4}}\\\\\rightarrow x+iy=(-625+0i)^{\frac{1}{4}}\\\\ x=r \cos A\\\\y=r \sin A\\\\r \cos A=-625\\\\ r \sin A=0\\\\x^2+y^2=625^{2}\\\\r^2=625^{2}\\\\|r|=625\\\\ \tan A=\frac{0}{-625}\\\\ \tan A=0\\\\ A=\pi\\\\\rightarrow z= [625(\cos (2k \pi+pi) +i \sin (2k\pi+ \pi)]^{\frac{1}{4}}\\\\k=0,1,2,3,4,....\\\\\rightarrow z=(625)^{\frac{1}{4}}[\cos \frac{(2k \pi+pi)}{4} +i \sin \frac{(2k\pi+ \pi)}{4}]$

$\rightarrow z_{0}=(625)^{\frac{1}{4}}[\cos \frac{pi}{4} +i \sin \frac{\pi)}{4}]\\\\\rightarrow z_{1}=(625)^{\frac{1}{4}}[\cos \frac{3\pi}{4} +i \sin \frac{3\pi}{4}]\\\\ \rightarrow z_{2}=(625)^{\frac{1}{4}}[\cos \frac{5\pi}{4} +i \sin \frac{5\pi}{4}]\\\\ \rightarrow z_{3}=(625)^{\frac{1}{4}}[\cos \frac{7\pi}{4} +i \sin \frac{7\pi}{4}]$

Argument of Complex number

Z=x+iy , is given by

If, x>0, y>0, Angle lies in first Quadrant.

If, x<0, y>0, Angle lies in Second Quadrant.

If, x<0, y<0, Angle lies in third Quadrant.

If, x>0, y<0, Angle lies in fourth Quadrant.

We have to find those roots among four roots whose argument is between 270° and 360°.So, that root is

$\rightarrow z_{2}=(625)^{\frac{1}{4}}[\cos \frac{5\pi}{4} +i \sin \frac{5\pi}{4}]$

5 0

3 years ago

Bethanine left at 3:00 in the afternoon and walked 3/10 of a mile to Bridget's house. Laney walked 36/100 of a mile to Bridget's

jarptica [38.1K]

Answer:

Bethanie and Laney walked a total of = 0.66 miles or ( $\frac{33}{50}$ th of a mile)

Step-by-step explanation:

Bethanie walked 3/10th of a mile

Laney walked 36/100th of a mile

Lets divide and convert them to decimal:

3 divided by 10 gives us 0.30

36 divided by 100 gives 0.36

Total they walked:

0.30 + 0.36 = 0.66 miles

That would be (in fraction):

66/100 = 33/50 of a mile

8 0

3 years ago

A² + b² = 7b and b² + (2b-a)² = 7² find (a - b)².

Mamont248 [21]

Answer:

(a - b)^2 = 49 - 4b^2 +2ab

Step-by-step explanation:

Given: a^2 + b^2 = 7b (assuming A is really “a”)

b^2 + (2b - a)^2 = 7^2

Find; (a - b)^2

Plan: Use Algebraic Manipulation

Start with b^2 + (2b - a)^2 = 7^2 =>

b^2 + 4b^2 - 4ab + a^2 = 49 by expanding the binomial.

a^2 + b^2 + 4b^2 - 4ab = 49 rearranging terms

a^2 + b^2 -2ab - 2ab + 4b^2 = 49 =>

a^2 - 2ab + b^2 = 49 - 4b^2 +2ab rearranging and subtracting 4b^2 and adding 2ab to both sides of the equation and by factoring a^2 - 2ab + b^2

(a - b)^2 = 49 - 4b^2 +2ab

Double Check: recalculated ✅ ✅

(a - b)^2 = 49 - 4b^2 +2ab

4 0

3 years ago