Which of the following describes all values of x for which 1-x2≥0?
সমাধান
সঠিক উত্তর: Option E
1-x^2 >= 0
---> x^2-1<=0
--> (x+1)(x-1)<=0
Above equation true for
i) x+1<=0 and x-1>=0
---> x<= -1 and x>=1
---> this is not possible ---Strike out this solution
ii) x+1>=0 and x-1<=0
---> x>=-1 and x<=1
--> -1<=x<=1
