Let f ( x ) = sin ( x ) + a x 2 {\displaystyle \displaystyle f(x)=\sin(x)+ax^{2}} . Which of the following conditions describes all values of a for which f HAS inflection points?
(a) | a | > 1 2 {\displaystyle \displaystyle |a|>{\tfrac {1}{2}}}
(b) a > 1 2 {\displaystyle \displaystyle a>{\tfrac {1}{2}}}
(c) a ≥ 1 2 {\displaystyle a\geq {\tfrac {1}{2}}}
(d) | a | < 1 2 {\displaystyle |a|<{\tfrac {1}{2}}}
(e) | a | ≤ 1 2 {\displaystyle |a|\leq {\tfrac {1}{2}}}
. Which of the following conditions describes all values of a for which f HAS inflection points?
