Step 1: Substitute the given values of Z1 and Z2.
Z2Z1=2−i2+3i
Step 2: Multiply the numerator and denominator by the conjugate of the denominator. The conjugate of 2−i is 2+i.
2−i2+3i×2+i2+i
Step 3: Expand the numerator and the denominator.
Numerator:
(2+3i)(2+i)=2(2)+2(i)+3i(2)+3i(i)=4+2i+6i+3i2
Since i2=−1:
=4+8i−3=1+8i
Denominator:
(2−i)(2+i)=22−i2=4−(−1)=4+1=5
Step 4: Combine the results.
Z2Z1=51+8i=51+58i
The expression in the form a+bi is 51+58i.
b) Find the modulus and argument of Z1×Z2.
Step 1: Calculate the product Z1×Z2.
Z1×Z2=(2+3i)(2−i)=2(2)+2(−i)+3i(2)+3i(−i)=4−2i+6i−3i2
Since i2=−1:
=4+4i−3(−1)=4+4i+3=7+4i
Step 2: Find the modulus of Z1×Z2. For a complex number x+yi, the modulus is x2+y2.
∣Z1×Z2∣=∣7+4i∣=72+42=49+16=65
Step 3: Find the argument of Z1×Z2. For a complex number x+yi in the first quadrant, the argument is tan−1(xy).
Since 7+4i is in the first quadrant (real part positive, imaginary part positive):
arg(Z1×Z2)=tan−1(74)
The modulus is 65 and the argument is tan−1(74).
c) Given also that Z3 is a complex number such that ∣Z3∣=5 and arg(Z3)=3π, express Z3Z1×Z2 in polar form.
Step 1: From part b), we have Z1×Z2=7+4i.
Its modulus is ∣Z1×Z2∣=65.
Its argument is arg(Z1×Z2)=tan−1(74).
Step 2: We are given Z3 in polar form:
∣Z3∣=5arg(Z3)=3π
Step 3: To find the modulus of the quotient Z3Z1×Z2, divide their moduli.
Z3Z1×Z2=∣Z3∣∣Z1×Z2∣=565
Step 4: To find the argument of the quotient Z3Z1×Z2, subtract their arguments.
arg(Z3Z1×Z2)=arg(Z1×Z2)−arg(Z3)=tan−1(74)−3π
Step 5: Express the result in polar form, r(cosθ+isinθ).
Z3Z1×Z2=565(cos(tan−1(74)−3π)+isin(tan−1(74)−3π))
The expression in polar form is 565(cos(tan−1(74)−3π)+isin(tan−1(74)−3π)).
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This mathematics problem involves applying core mathematical principles and formulas. Below you will find a complete step-by-step solution with detailed explanations for each step, helping you understand not just the answer but the method behind it.
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Here's the solution to question 8: Given complex numbers Z_1 = 2 + 3i and Z_2 = 2 - i. a) Express (Z_1)/(Z_2) in the form a + bi where a, b R. Step 1: Substitute the given values of Z_1 and Z_2. (Z_1)/(Z_2) = (2 + 3i)/(2 - i) Step 2: Multiply the numerator and denominator by the conjugate of the denominator. The conjugate of 2 - i is 2 + i. (2 + 3i)/(2 - i) × (2 + i)/(2 + i) Step 3: Expand the numerator and the denominator. Numerator: (2 + 3i)(2 + i) = 2(2) + 2(i) + 3i(2) + 3i(i) = 4 + 2i + 6i + 3i^2 Since i^2 = -1: = 4 + 8i - 3 = 1 + 8i Denominator: (2 - i)(2 + i) = 2^2 - i^2 = 4 - (-1) = 4 + 1 = 5 Step 4: Combine the results. (Z_1)/(Z_2) = (1 + 8i)/(5) = (1)/(5) + (8)/(5)i The expression in the form a + bi is (1)/(5) + (8)/(5)i. b) Find the modulus and argument of Z_1 × Z_2. Step 1: Calculate the product Z_1 × Z_2. Z_1 × Z_2 = (2 + 3i)(2 - i) = 2(2) + 2(-i) + 3i(2) + 3i(-i) = 4 - 2i + 6i - 3i^2 Since i^2 = -1: = 4 + 4i - 3(-1) = 4 + 4i + 3 = 7 + 4i Step 2: Find the modulus of Z_1 × Z_2. For a complex number x + yi, the modulus is sqrt(x^2 + y^2). |Z_1 × Z_2| = |7 + 4i| = sqrt(7^2 + 4^2) = sqrt(49 + 16) = sqrt(65) Step 3: Find the argument of Z_1 × Z_2. For a complex number x + yi in the first quadrant, the argument is ^-1((y)/(x)). Since 7 + 4i is in the first quadrant (real part positive, imaginary part positive): (Z_1 × Z_2) = ^-1((4)/(7)) The modulus is sqrt(65) and the argument is ^-1((4)/(7)). c) Given also that Z_3 is a complex number such that |Z_3| = 5 and (Z_3) = ()/(3), express (Z_1 × Z_2)/(Z_3) in polar form. Step 1: From part b), we have Z_1 × Z_2 = 7 + 4i. Its modulus is |Z_1 × Z_2| = sqrt(65). Its argument is (Z_1 × Z_2) = ^-1((4)/(7)). Step 2: We are given Z_3 in polar form: |Z_3| = 5 (Z_3) = ()/(3) Step 3: To find the modulus of the quotient (Z_1 × Z_2)/(Z_3), divide their moduli. |(Z_1 × Z_2)/(Z_3)| = (|Z_1 × Z_2|)/(|Z_3|) = sqrt(65)5 Step 4: To find the argument of the quotient (Z_1 × Z_2)/(Z_3), subtract their arguments. ((Z_1 × Z_2)/(Z_3)) = (Z_1 × Z_2) - (Z_3) = ^-1((4)/(7)) - ()/(3) Step 5: Express the result in polar form, r( + i ). (Z_1 × Z_2)/(Z_3) = sqrt(65)5 ( (^-1((4)/(7)) - ()/(3)) + i (^-1((4)/(7)) - ()/(3)) ) The expression in polar form is sqrt(65)5 ( (^-1((4)/(7)) - ()/(3)) + i (^-1((4)/(7)) - ()/(3)) ).