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Zorluk: Çok zorComplex Numbers and Operations

For the imaginary unit ii, where i2=1i^2 = -1, and any integer nn, what is the value of the expression i4n+3(1+i)8(1i)6\frac{i^{4n+3} (1 + i)^8}{(1 - i)^6}?

  1. -2Cevap
  2. B
    2
  3. C
    -i
  4. D
    -2i
  5. E
    2i

Cevap

2-2
To find the value of the expression, we simplify each part. First, i4n+3i^{4n+3} simplifies to i-i because i4n=1i^{4n} = 1 and i3=ii^3 = -i. Second, (1+i)8(1+i)^8 is simplified by first squaring the base to get (1+i)2=2i(1+i)^2 = 2i, and then raising the result to the fourth power: (2i)4=16(2i)^4 = 16. Third, (1i)6(1-i)^6 is simplified by first squaring the base to get (1i)2=2i(1-i)^2 = -2i, and then cubing the result: (2i)3=8i3=8i(-2i)^3 = -8i^3 = 8i. Substituting these back into the expression yields i168i=2\frac{-i \cdot 16}{8i} = -2. Thus, the expression simplifies to 2-2.

Adım Adım Çözüm

1
Simplify the term i4n+3i^{4n+3} using the properties of powers of ii.
i4n+3=ii^{4n+3} = -i
Since i4=1i^4 = 1, we can rewrite i4n+3i^{4n+3} as (i4)ni3=1n(i)=i(i^4)^n \cdot i^3 = 1^n \cdot (-i) = -i.
2
Simplify the numerator term (1+i)8(1+i)^8.
(1+i)8=16(1+i)^8 = 16
We can rewrite (1+i)8(1+i)^8 as ((1+i)2)4((1+i)^2)^4. Since (1+i)2=1+2i+i2=2i(1+i)^2 = 1 + 2i + i^2 = 2i, we have (2i)4=24i4=161=16(2i)^4 = 2^4 \cdot i^4 = 16 \cdot 1 = 16.
3
Simplify the denominator term (1i)6(1-i)^6.
(1i)6=8i(1-i)^6 = 8i
We can rewrite (1i)6(1-i)^6 as ((1i)2)3((1-i)^2)^3. Since (1i)2=12i+i2=2i(1-i)^2 = 1 - 2i + i^2 = -2i, we have (2i)3=(2)3i3=8(i)=8i(-2i)^3 = (-2)^3 \cdot i^3 = -8 \cdot (-i) = 8i.
4
Substitute the simplified components back into the original expression and divide.
i168i=2\frac{-i \cdot 16}{8i} = -2
Substituting the terms gives i168i\frac{-i \cdot 16}{8i}. The common factor of ii in the numerator and denominator cancels out, and dividing 16-16 by 88 yields 2-2.

Anahtar Kavram

Simplifying complex expressions involving powers of the imaginary unit and powers of complex binomials.
Tahmini Süre:1m 30s
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