What does #tan(arcsec(2))-2cos(arc cot(3))# equal?

1 Answer
Apr 20, 2016

#+-sqrt 3+-(3/5)sqrt 10# = 3.629, - 1.653, 0.1653 and -3.629, nearly.

Explanation:

If sec is positive, tan could be positive or negative.
Let #a=arc sec 2. sec a=2 and tan a=+-sqrt 3#.

So, the first term #tan(arc sec 2)=+-sqrt3#

If cot is positive, cos could be positive or negative.
Let #b=arc cot 3. cot b=3 and cos b=+-3/sqrt 10#.

So, the second term #-2 cos(arc cot 3)=-2 cos b=+-6/sqrt 10#.

Remembering that the sign choice from #+-# is independent for each term,
the sum is #+-sqrt 3+-6/sqrt 10=+-3.629, +-1.653#, nearly. . .