dse 2010 doubt

Posted by Nam on Jun 13, 2014; 6:47pm
URL: http://discussion-forum.276.s1.nabble.com/dse-2010-doubt-tp7592653.html

Suppose the function f: R-> R is given by f(x)=x^3-3x+b. Find the number of points in closed interval [-1,1] at which f(x)=0.
1)none
2)at most one
3)one
4)at least one