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Grade 12IIT JEE Entrance Exam

Is period of fogx always same as period of gx? Pls answer. I'm not getting it as true for all times

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Profile image of Jeshlin Donna
6 Years agoGrade 12
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3 Answers

Profile image of Arun
6 Years ago
Dear student
 
yes it is true
 
as let g(x) has period T
then fog (x+T) = fog (x)
 
hence fog(x) is also periodic woth period T
Profile image of Aditya Gupta
6 Years ago
dear student, aruns answer is clearly incorrect.
we know that the period of a function h(x) is the smallest positive value T such that
h(x+T)= h(x) for all x.
now let g(x)= sinx and f(x)= cosx.
clearly period of g(x) is 2pi.
but period of fog(x)= cos(sinx) is pi bcoz fog(x+pi)= cos(sin(x+pi))= cos( – sinx)= cos(sinx)= fog(x).
Hence, period of fog need not be same as period of g.
kindly approve :)))