Q. Which of the following is equivalent to the complex number i15 ?Choose 1 answer:(A) 1(B) i(C) −1(D) −i
Define i as Imaginary Unit: To solve for i15, we need to remember that i is the imaginary unit, which is defined by i2=−1. We can simplify i15 by breaking it down into powers of i2.
Find Largest Multiple of 4: First, we find the largest multiple of 4 that is less than or equal to15, because i4=(i2)2=(−1)2=1. The largest multiple of 4 less than or equal to 15 is 12.
Express i15 as i3: We can express i15 as i12×i3. Since i12 is a multiple of i4, it simplifies to 1. So, i15 simplifies to i3.
Simplify i3: Now we need to simplify i3. We know that i2=−1, so i3=i2⋅i=−1⋅i=−i.
Final Answer: Therefore, i15 is equivalent to −i, which corresponds to answer choice (D).
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