Q . I f f ( x ) = 2 cos x - 1 cos x - 1 , x ≠ π 4 . F i n d t h e v a l u e o f f π 4 s o t h a t f ( x ) b e c o m e s c o n t i n u o u s a t x = π / 4 . Share with your friends Share 0 Shruti Tyagi answered this Dear Student, There is no formula being used here. we are using the concept of continous function. for a function f(x) to be continous at point x=awe should have limx→a-fx=limx→a+fx=limx→afx=faHence here we need to find the continuity of f(x) at x=π4Hence limx→π4fx=fπ4 Regards, -1 View Full Answer