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Grade 12Algebra

For what value of 'a' do the roots of the equation cos x = a form an AP

Profile image of Samir Madan
12 Years agoGrade 12
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1 Answer

Profile image of bharat bajaj
12 Years ago
cos x = a ⇒ x = 2nπ ± cos-1a
When a= - 1
x = 2nπ + cos-1(-1)
x = 2nπ + π where n ∈ I
x = ..., - 3π, -π, π, 3π, ... , which is an AP
Hence, a = -1..
Thanks&Regards
Bharat Bajaj
askiitian faculty
IIT Delhi