Find arctan(tan 15° * tan 21° * tan 27°).
The product: (tan 15*tan21*tan27) is approximately:
-4.28046154195 (correct to 11 places) and:
arctan(-4.28046154195) is:
approximately- equal to -1.34129286142 (correct to 11 places) degrees , which seems to be the desired end result.
I have neither been able to derive the end result analytically nor have I been able to fathom its significance.
Edited on May 14, 2022, 11:25 pm
By Scientific Hand Calculator