Range of the function `f(x)=cos^(-1)x+2cot^(-1)x+3cosec^(-1)x` is equal to

Range of the function `f(x)=cos^(-1)x+2cot^(-1)x+3cosec^(-1)x` is equal to
Range of the function `f(x)=cos^(-1)x+2cot^(-1)x+3cosec^(-1)x` is equal to
Range of the function `f(x)=cos^(-1)x+2cot^(-1)x+3cosec^(-1)x` is equal to
Range of the function `f(x)=cos^(-1)x+2cot^(-1)x+3cosec^(-1)x` is equal to

equal