How do you find the exact values of cot, csc and sec for 90 degrees?

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Answer 1 · 2018-04-13T17:27:37

#color(blue)(csc(90^@)=1)#

Identities:

#color(red)bb(cotx=1/tanx)#

#color(red)bb(cscx=1/sinx)#

#color(red)bb(secx=1/cosx)#

We know:

#sin(90^@)=1#

#cos(90^@)=0#

#tan(90^@)# is undefined. This is because:

as #theta->90^@, tan(theta)->oo#

#:.#

#csc(90^@)=1/1=color(blue)(1)#

#sec(90^@)=1/0# This is also undefined. ( division by zero )

#cot(90^@)# This is also undefind, because #tan(90^@)# is undefined.