The range of the function f(x)=cos2x4+sinx4,xϵR is
f(x)=1−sin2x4+sinx4=−{sin2x4−sinx4}+1=−{(sinx4−12)2−14}+1=54−(sinx4−12)2Maximum f(x)=54Minimum f(x)=54=(−1−12)2=54−94=−1Range of f(x)=[−1,54]