find angle

1 Answers

(x-a).(x+a)=-|a|²=|x|²-1=8

implies |x|=3 (1)

(x-a).(x+a)=8
|(x-a)||(x+a)|cosÎ¸=8 (2)

x.a=2 impies |x||a|cosÎ±=2

that gives cosÎ±=2/3

(x-a)X(x+a)=2*(xXa)
|(x-a)X(x+a)|=|(x-a)||(x+a)|sinÎ¸=|2xXa|=2|x|sinÎ± (3)

from (1) (2) and (3)
8tanÎ¸=2*3*âˆš(5/9)
tanÎ¸=âˆš5/4

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