If true than why b is not the solution in question
what do u mean by absolute minima?
These are all local minima or maxima
Can u tell ur question more clearly?
Please check this also http://tutorial.math.lamar.edu/Classes/CalcI/MinMaxValues.aspx
I had read that for local minima we should not check at end points of given interval but than why we are considering here pi/4 for local minima
Also see this https://gateoverflow.in/84016/maths-local-maxima-minima
@ shivangi5 Local maxima/minima are some points in the graph where if you restrict the domain of a particular graph then in that particular domain they represent the respective values. But since we are not considering the entire domain we are not sure whether local minima and maxima are absolute or not ! Thus to go for we consider complete domain to find global values.