Q. 75.0( 1 Vote )

Mark the correct alternative in the following:

The range of f(x) = cos [x], for -π/2< x <π/2 is

A. {-1, 1, 0}

B. {cos 1, cos 2, 1}

C. {cos 1, -cos 1, 1}

D. [-1, 1]

Answer :


[x]= -2


f(x)= cos[x]= cos(-2)


= cos2


because cos(-x)= cos(x)


for-1 ≤x<0


[x]=-1


f(x)= cos[x]


=cos(-1)


= cos1


for 0 ≤x< 1


[x]=0


f(x) = cos 0


=1



[x]=1


f(x)=cos 1


Therefore, R(f) = {1, cos 1,cos 2}


Option B is correct.

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