Given Z = (5+i)/(2+3i). To express this in the form x+yi, multiply the numerator and denominator by the conjugate of the denominator. The conjugate of 2+3i is 2-3i.
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Given Z = (5+i)/(2+3i). To express this in the form x+yi, multiply the numerator and denominator by the conjugate of the denominator. The conjugate of 2+3i is 2-3i.
ScanSolve AI Answer
Answer
1-i
Step 1: Express Z in the form x+yi.
Given Z=2+3i5+i. To express this in the form x+yi, multiply the numerator and denominator by the conjugate of the denominator. The conjugate of 2+3i is 2−3i.
Z=2+3i5+i×2−3i2−3iZ=(2+3i)(2−3i)(5+i)(2−3i)
Expand the numerator:
(5+i)(2−3i)=5(2)+5(−3i)+i(2)+i(−3i)=10−15i+2i−3i2
Since i2=−1:
=10−13i−3(−1)=10−13i+3=13−13i
Expand the denominator using the difference of squares formula (a+b)(a−b)=a2−b2:
(2+3i)(2−3i)=22−(3i)2=4−9i2
Since i2=−1:
=4−9(−1)=4+9=13
Now substitute the expanded numerator and denominator back into the expression for Z:
Z=1313−13iZ=1313−1313iZ=1−ia) The complex number Z in the form x+yi is 1−i.
Step 2: Show that Z=2(cos4π−isin4π).
From part (a), we have Z=1−i.
To express a complex number x+yi in polar form r(cosθ+isinθ), we find the modulus r=x2+y2 and the argument θ=arctan(xy) (adjusted for quadrant).
For Z=1−i, we have x=1 and y=−1.
Calculate the modulus r:
r=12+(−1)2r=1+1r=2
Calculate the argument θ:
Since x=1 (positive) and y=−1 (negative), Z lies in the fourth quadrant.
The reference angle α is given by tanα=xy=1−1=1.
So, α=4π.
For a complex number in the fourth quadrant, θ=−α.
θ=−4π
Now substitute r and θ into the polar form r(cosθ+isinθ):
Z=2(cos(−4π)+isin(−4π))
Using the trigonometric identities cos(−θ)=cosθ and sin(−θ)=−sinθ:
Z=2(cos4π−isin4π)b) We have shown that Z=2(cos4π−isin4π).
Step 3: By equating the form in (a) to that in (b), show that cos4π=21.
From part (a), Z=1−i.
From part (b), Z=2(cos4π−isin4π).
Equate the two expressions for Z:
1−i=2(cos4π−isin4π)1−i=2cos4π−i2sin4π
For two complex numbers to be equal, their real parts must be equal and their imaginary parts must be equal.
Equating the real parts:
1=2cos4π
Divide by 2:
cos4π=21c) We have shown that cos4π=21.
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Express Z in the form x+yi. Given Z = (5+i)/(2+3i).
Given Z = (5+i)/(2+3i). To express this in the form x+yi, multiply the numerator and denominator by the conjugate of the denominator. The conjugate of 2+3i is 2-3i.
This languages problem is solved step by step below, with detailed explanations to help you understand the method and arrive at the correct answer.
ScanSolve AI Answer
Step 1: Express Z in the form x+yi. Given Z = (5+i)/(2+3i). To express this in the form x+yi, multiply the numerator and denominator by the conjugate of the denominator. The conjugate of 2+3i is 2-3i. Z = (5+i)/(2+3i) × (2-3i)/(2-3i) Z = ((5+i)(2-3i))/((2+3i)(2-3i)) Expand the numerator: (5+i)(2-3i) = 5(2) + 5(-3i) + i(2) + i(-3i) = 10 - 15i + 2i - 3i^2 Since i^2 = -1: = 10 - 13i - 3(-1) = 10 - 13i + 3 = 13 - 13i Expand the denominator using the difference of squares formula (a+b)(a-b) = a^2-b^2: (2+3i)(2-3i) = 2^2 - (3i)^2 = 4 - 9i^2 Since i^2 = -1: = 4 - 9(-1) = 4 + 9 = 13 Now substitute the expanded numerator and denominator back into the expression for Z: Z = (13 - 13i)/(13) Z = (13)/(13) - (13i)/(13) Z = 1 - i a) The complex number Z in the form x+yi is 1-i. Step 2: Show that Z = sqrt(2)(()/(4) - i()/(4)). From part (a), we have Z = 1 - i. To express a complex number x+yi in polar form r( + i), we find the modulus r = sqrt(x^2+y^2) and the argument = ((y)/(x)) (adjusted for quadrant). For Z = 1 - i, we have x=1 and y=-1. Calculate the modulus r: r = sqrt(1^2 + (-1)^2) r = sqrt(1+1) r = sqrt(2) Calculate the argument : Since x=1 (positive) and y=-1 (negative), Z lies in the fourth quadrant. The reference angle is given by = |(y)/(x)| = |(-1)/(1)| = 1. So, = ()/(4). For a complex number in the fourth quadrant, = -. = -()/(4) Now substitute r and into the polar form r( + i): Z = sqrt(2)((-()/(4)) + i(-()/(4))) Using the trigonometric identities (-) = and (-) = -: Z = sqrt(2)(()/(4) - i()/(4)) b) We have shown that Z = sqrt(2)(()/(4) - i()/(4)). Step 3: By equating the form in (a) to that in (b), show that ()/(4) = (1)/(sqrt(2)). From part (a), Z = 1 - i. From part (b), Z = sqrt(2)(()/(4) - i()/(4)). Equate the two expressions for Z: 1 - i = sqrt(2)(()/(4) - i()/(4)) 1 - i = sqrt(2)()/(4) - isqrt(2)()/(4) For two complex numbers to be equal, their real parts must be equal and their imaginary parts must be equal. Equating the real parts: 1 = sqrt(2)()/(4) Divide by sqrt(2): ()/(4) = (1)/(sqrt(2)) c) We have shown that ()/(4) = (1)/(sqrt(2)).