How do you find the exact values of #costheta# and #sintheta# when #tantheta=0#?

1 Answer
Feb 21, 2018

Answer:

#sin theta =0#, #cos theta = pm 1# - that's all that can be said from #tan theta = 0# in the absence of any other information.

Explanation:

Since #tan theta = {sin theta}/{cos theta}#,

#tan theta = 0 implies sin theta =0#

Thus

#cos^2 theta = 1-sin^2 theta =1#

And so #cos theta = pm #

Actually #tan theta =0# tells you that #theta# is a multiple of #pi#. If it is an odd multiple, (like #pi#, #3pi# etc)) #cos theta# will be -1, otherwise it will be +1.