Math Problem Statement

Is 1 correct?

Is 1 correct?

Solution

Let's carefully verify Problem 1: i9+4i3(42i)i^9 + 4i^3 - (4 - 2i).

Step-by-step Solution:

  1. Simplify i9i^9: Recall the cyclic nature of powers of ii: i1=i,i2=1,i3=i,i4=1(repeats every 4 powers).i^1 = i, \quad i^2 = -1, \quad i^3 = -i, \quad i^4 = 1 \quad \text{(repeats every 4 powers)}. Since 9÷49 \div 4 leaves a remainder of 11, we have: i9=i1=i.i^9 = i^1 = i.

  2. Simplify 4i34i^3: From the cycle above, i3=ii^3 = -i. Thus: 4i3=4(i)=4i.4i^3 = 4(-i) = -4i.

  3. Expand (42i)-(4 - 2i): Distribute the negative sign: (42i)=4+2i.-(4 - 2i) = -4 + 2i.

  4. Combine all terms: Substitute the simplified components: i9+4i3(42i)=i4i4+2i.i^9 + 4i^3 - (4 - 2i) = i - 4i - 4 + 2i. Combine like terms:

    • For imaginary parts: i4i+2i=ii - 4i + 2i = -i.
    • For real parts: 4-4.

    Final result: 4i.-4 - i.


Is the original answer correct?

The student's final answer is written as 63i2-6 - 3i^2, but this is incorrect. The correct answer is: 4i.\boxed{-4 - i}.


Would you like a detailed explanation of any step or assistance with the other problems?

Related Questions:

  1. How does the cycle of powers of ii (i.e., i,1,i,1i, -1, -i, 1) work?
  2. Can you simplify i20+i25i^{20} + i^{25}?
  3. What are common mistakes when distributing negative signs in complex numbers?
  4. How can we graphically represent 4i-4 - i on the complex plane?
  5. What happens if we multiply 4i-4 - i by its complex conjugate?

Tip: Memorizing the cyclic powers of ii is key to solving problems involving higher powers of ii.

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Math Problem Analysis

Mathematical Concepts

Complex Numbers
Powers of i
Simplification

Formulas

Powers of i: i^1 = i, i^2 = -1, i^3 = -i, i^4 = 1

Theorems

Properties of imaginary unit i

Suitable Grade Level

Grades 10-12