question_answer

The function \[\mathbf{f}\left( \mathbf{x} \right)={{\mathbf{x}}^{\mathbf{9}}}+\mathbf{3}{{\mathbf{x}}^{\mathbf{7}}}+\mathbf{64}\]is increasing on:

A)  \[\left( 0,\infty  \right)\]               

B)  \[\left( -\infty ,0 \right)\]       

C)  \[\left( -\infty ,\infty  \right)\]                   

D)   None of these