Answer:
5
Step-by-step explanation:
Answer:
Expand it.
(1+2i)^3 is equal to (1+2i)(1+2i)(1+2i).
Multiply everything out (being sure to multiply <em>every</em> term. (1+2i) * (1+2i) = 1+2i+2i+4i^2.
i is the square root of negative one, so i^2 is just -1. 1+2i+2i-4 is what you get from the first two, so now simplify that:
1-4 + 2i+2i = (-3+4i) and now multiply that by (1+2i):
(-3+4i) * (1+2i) = -3 - 6i +4i +8i^2.
Simplify again, and the answer is: -11-2i
Step-by-step explanation:
I hope this helps - really my only tip is don't spend time thinking about what i is, that just hurts your brain. Just remember that i^2 is equal to negative one, and treat it like regular multiplication and you will be fine.
Answer:
165 ways
Step-by-step explanation:
Selection deals with combination
There are a total of 11 from which 3 are to be selected
11C3 = 11!/3!(11-3)!
= 11!/(3!x8!)
=(11x10x9x8!)/(3x2x8!)
=11x10x9/6
=11x5x3 = 165 ways
Full turn = 360°
Number of 90° = 360 ÷ 90 = 4
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Answer: It takes 4 90° to make a full turn.
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