SOLUTION: write the expression in the standard form a+bi: 2i^15-i^7.

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Question 948046: write the expression in the standard form a+bi: 2i^15-i^7.
Found 2 solutions by CubeyThePenguin, greenestamps:
Answer by CubeyThePenguin(3113) About Me  (Show Source):
You can put this solution on YOUR website!
Patterns of powers of i:

i^0 = 1
i^1 = i
i^2 = -1
i^3 = -i


2i^15 - i^7 = 2(-i) - i = -3i

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


Tutor @CubeyThePenguin has supplied another careless response with a wrong answer....

i^15 = (i^12)(i^3) = (1)(-i) = -i

i^7 = (i^4)(i^3) = (1)(-i) = -i

So

2i^15 - i^7 = 2(-i)-(-i) = -2i+i = -i