Q. Which of the following is equivalent to the complex number i19 ?Choose 1 answer:(A) 1(B) i(C) −1(D) −i
Definition of i: To solve for i19, we need to remember that i is the imaginary unit, which is defined by i2=−1. We can use the powers of i to simplify i19 by finding a pattern.
Pattern of powers of i: The powers of i repeat in a cycle: i1=i, i2=−1, i3=−i, and i4=1. Then the cycle repeats because i5=i, i6=−1, and so on.
Finding i19: To find i19, we can divide 19 by 4 to find how many full cycles of 4 there are and what the remainder is. The remainder will tell us the equivalent power of i that we need to find.19÷4=4 remainder 3. This means i19 is equivalent to i4⋅4+3, which is the same as i190.
Simplifying i19: Since i4×4 is a full cycle repeated 4 times, it is equivalent to 1. So we only need to consider i3.i3=−i.
Final result: Therefore, i19 is equivalent to i4⋅4⋅i3, which simplifies to 1⋅−i, or just −i.
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