MadSci Network: Physics |
Yes. All numbers are in our imagination. So in that sense "real" numbers are just as imaginary as "imaginary" numbers. The term imaginary was applied when it was noticed that these numbers are neither less than or greater than zero. The real numbers were pictured as being on an infinitely long line. A point on that line was thought as the middle of the line, and labelled as zero. Positive numbers were to the right of zero. Negative numbers were to the left of zero. Imaginary numbers could not be pictured as on the line at all. Since nobody knew, at the time, how to picture imaginary numbers, it made sense to call them imaginary. Later it was figured out that we could picture the imaginary numbers by placing them on a line perpendicular to the real number line. Another infinitely long line perpendicular to the real number line goes through the zero point. So zero is the zero for both real numbers and for imaginary numbers. George Gamow's book talks a little bit about this representation of imaginary numbers and also talks about adding imaginary numbers to real numbers to make complex numbers. Another important point is that the square root of -1 is still one unit away from zero. It is just that it is one unit away in the vertical or "imaginary" direction.
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