Let `f: Rvec` be a differentiable function `AAx in R` . If the tangent drawn to the curve at any point `x in (a , b)` always lies below the curve, then `f^(prime)(x)<0,f^(x)<0AAx in (a , b)` `f^(prime)(x)>0,f^(x)>0AAx in (a , b)` `f^(prime)(x)>0,f^(x)>0AAx in (a , b)` `non eoft h e s e`

Answer

3

Explanation

Clearly for`f(x) gt0 f''(x) gt0` [in figure (c ) tangent always lies below the graph
For `f'(x) lt0, f''(x) lt["in figure" (d)]` tangent always lies below the graph.