Question #381c9

1 Answer
Feb 11, 2018

x can occupy values
#(-oo...........-5pi#to#-3pi#, #-3pi#to#-pi#,#-pi#to#pi#, #pi#to#3pi#,#3pi#to#5pi,.............oo)#

Explanation:

Given:
#f(x)=sqrtsin(cosx)#
requires that the number inside the square root to be positive
ie
#sin(cosx)>0#
The function sin is positive in first and second quadrant, thereby the values in third and fourth quadrant being prohibited

Further,
#cosx# can have 1 as the maximum value
and
cos x is positive in first and fourth quadrants
x can occupy values..........#-5pi#to#-3pi#, #-3pi#to#-pi#,#-pi#to#pi#, #pi#to#3pi#,#3pi#to#5pi#,............
ie#(-oo...........-5pi#to#-3pi#, #-3pi#to#-pi#,#-pi#to#pi#, #pi#to#3pi#,#3pi#to#5pi,.............oo)#