Question #ac2da

1 Answer
Aug 10, 2016

No such #theta# exists.

Explanation:

It is an identity that #cos^2(theta) + sin^2(theta) = 1# for all #theta#, thus no #theta# will result in the given equality.


In the real numbers, there is also the reasoning that
#-1<=cos(theta)<=1# and #-1<=sin(theta)<=1#
#=>#
#0 <= cos^2(theta) <= 1# and #0<=sin^2(theta)<=1#.

Then, even if we allow different angles, for any #theta, gamma in RR# (the real numbers):

#cos^2(theta)+sin^2(gamma) <= 1+1 = 2#


Even if we allow for complex arguments, however, which allow for greater values of sine and cosine, the original identity still holds, meaning there is still no #theta# fulfilling #cos^2(theta)+sin^2(theta)=3#.