What is the sum of #sqrt(-2)# and #sqrt(-18)#?

1 Answer
A. S. Adikesavan
Apr 10, 2016

#+-5.657i and +-2.8281, i=sqrt(-1)#.

Explanation:

If #x^2=-1=i^2, x=sqrt(-1)=(-1)^(1/2)=+-#i
#sqrt(-2)=sqrt(-1)sqrt2=+-1.4142i and, likewise, sqrt(-18)=+-3(1.4142)i#.
So, the sum is #+-1.4142(1+-3)i=+-5.657i and +-2.8281, i=sqrt(-1)#, nearly..

I am sorry. Don't curse me feeling that I am making a mole appear as mountain. Truly, each term has two values and the sum has four values, in Mathematical Exactitude.

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