If $f(x)=a\cos (bx+c)+d$, then what is the range of f(x)?
Answer & explanation
Correct answer: option 2
$f(x)=a\cos (bx+c)+d$ . . . .(i)
For minimum $\cos (bx+c)=-1$
From (i), $f(x)=-a+d=(d-a)$
For maximum $\cos (bx+c)=1$
From (i), $f(x)=a+d=(d+a)$
Range of $f(x)=[d-a,d+a]$