Question

9.
Find the real value of 'a' for which 3i^3 - 2ai^2 + (1 - a)i + 5 is real.
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Answer 1

Answer:

(i) 3i3 – 2ai2 + (1 – a)i + 5 = –3i + 2a + 5 + (1 – a)i = 2a + 5 + (– a – 2) i, which is real if – a – 2 = 0 i.e. a = – 2.