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COMPLEX NUMBERS

COMPLEX NUMBERS

by aditya gopi -
Number of replies: 2
The greatest and the least values of |z1 + z2| if z1 = 12+9i and |z2| = 7 are respectively?

(a) 22 and 8
(b) 20 and 8
(c) 22 and 10
(d) 25 and 8

Please give me the answer in detail.
In reply to aditya gopi

Re: COMPLEX NUMBERS

by Prashanth S -

Iz1 + z2I <= Iz1I + Iz2I

Iz1I = ( 122 + 92 )0.5 = 15

the greatest value of Iz1 + z2I = Iz1I + Iz2I

therefore the greatest value is 15+7  = 22

the least value is 15-7 = 8

the answer (according to me ) is (a)

reply if answer is correct or wrong