Which of the following functions is not decreasing on `(0,pi//2)?`

Which of the following functions is decreasing on (0, pi/2)

Which of the following functions is decreasing on (0,(pi)/(2)) ?

Which of the following function is decreasing on (0, pi/2)

Which of the following functions is decreasing on (0, (pi)/(2)) .

Which of the following function is decreasing of (0,(pi)/(2))

Which of the following functions are decreasing on (0,\ pi//2) ? (i) cosx (ii) cos2x (iii) tanx (iv) cos3x

Which of the following functions are decreasing on (0,\ pi//2) ? (i) cosx (ii) cos2x (iii) tanx (iv) cos3x