Q)(A)20   (B)2   (C) 1     (D)7

Asked by araima2001 | 16th Mar, 2017, 09:22: AM

Expert Answer:

begin mathsize 20px style we space know space that space straight omega space is space an space imaginary space cube space root space of space unity comma
straight omega squared equals straight omega
If space we space put space this space in space the space given space equations space we space get comma
sum from straight r equals 1 to 3 of fraction numerator 1 over denominator straight x subscript straight r plus straight omega end fraction equals 2 straight omega squared space becomes space sum from straight r equals 1 to 3 of fraction numerator 1 over denominator straight x subscript straight r plus straight omega end fraction equals 2 straight omega space
also comma
sum from straight r equals 1 to 3 of fraction numerator 1 over denominator straight x subscript straight r plus straight omega squared end fraction equals 2 straight omega space becomes space sum from straight r equals 1 to 3 of fraction numerator 1 over denominator straight x subscript straight r plus straight omega end fraction equals 2 straight omega
We space have space to space find space the space value space of space sum from straight r equals 1 to 3 of fraction numerator 1 over denominator straight x subscript straight r plus 1 end fraction.
Here comma space we space can space compare space the space given space equations space with space sum from straight r equals 1 to 3 of fraction numerator 1 over denominator straight x subscript straight r plus 1 end fraction comma
then space we space get space straight omega equals 1.
Hence comma space value space of space sum from straight r equals 1 to 3 of fraction numerator 1 over denominator straight x subscript straight r plus 1 end fraction space equals space 2 cross times 1 equals 2.
Answer space is space 2.

end style

Answered by Rebecca Fernandes | 19th Mar, 2017, 06:55: PM