How do you find the domain & range for #y=cscx#?

1 Answer
May 19, 2016

Please see below.

Explanation:

Cosecant function is closely tied to sine function, as it is its reciprocal. If we relate to coordinate plane, while sine function is #y/r#, cosecant function is #r/y# and problem arises when #y->0#, which happens when angle is #0# or #pi# or #2pi#, #3pi#, etc.

Hence, domain of #cscx# is given by

#x!=npi#, where #n# is an integer.

Again as cosecant function is #r/y# and as #r# in #r/y# is always positive and #r>y#, this function is always greater than or equal to #1# or less than or equal to #-1#.

Tis means, it never takes values between #1# and #-1#.

Further, it is equal to #1# when #x=2npi+pi/2# and is equal to #-1# when #x=2npi-pi/2#, where #n# is an integer.

The graph of #cscx# will appear as shown below.

graph{cscx [-10, 10, -5, 5]}