Algebra-5

if (√3+i)ⁿ=2ⁿ then n is

a) an integral multiple of 12
b)an integral multiple of 5
c)an integral multiple of 8
d)none

5 Answers

d ) I think but here 12 also satifies so ???[7]

u are wrong srinath

106

Asish Mahapatra ·2009-03-20 21:09:07

(2e^iÏ€/6)ⁿ = 2ⁿ
==> e^inÏ€/6 = 1
==> cos(nÏ€/6) + isin(nÏ€/6) = 1
==> cos(nÏ€/6) = 1 and sin(nÏ€/6) = 0
==> nÏ€/6 = 2mÏ€ and nÏ€/6 = nÏ€
==> n = 12m

(a)

oh haan . I took cos(Ï€/3) = âˆš3 /2 my mistake. :P

thanks asish

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