Posted by Marie on .
If cot 2(Theta) = 5/12 with 0 (less than or equal to) 2(Theta) (Less than or equal to) Pi, find the cos(Theta), sin(Theta), and tan(Theta).

Trigonometry 
Henry,
cot(2A) = X/Y = 5/12. Q1.
r^2 = 5^2 + 12^2 = 169
r = 13.
cos(2A) = X/r = 5/13.
sin(2A) = Y/r = 12/13.
tan(2A) = Y/X = 12/5.
cos2A = 2cos^2A1 = 5/13
2cos^2A = 5/13 + 1 = 18/13
cos^2A = 18/26
cosA = sqrt(18/26)
cosA = 3sqrt(2/26)
cosA = 3*sqrt(1/13).
sqrt = Square root.
sin(2A) = 2sinA*cosA = 12/13.
2sinA*3sqrt(1/13) = 12/13
sinA*3sqrt(1/13) = 12/26
sinA = (12/26)/(3sqrt(1/13)
sinA = (4/26)/(sqrt(1/13)
sinA = (2/13)/(sqrt(1/13)
sinA = (2/13)sqrt(1/13)/(1/13)
sinA = 2sqrt(1/13).