Double Angle Formulas
2tanu/(1-tan2u)
What is tan(2u)?
sin2u + cos2u
What is "1"?
1/2
What is sin(pi/6)?
opp/hyp
What is sinu?
(sq.root 2)/2 in Q1
What is sin(pi/4)? or What is cos(pi/4)?
cos2u - sin2u
What is cos(2u)?
1 + tan2u
What is sec2u?
(sq.root 3)/2
What is cos(pi/6)?
opp/adj
What is tanu?
(sq.root2)/2 in Q2
What is sin(3pi/4)?
2sinucosu
What is sin(2u)?
csc2u - 1
What is cot2u?
Not 30 degrees, but pi/6.
What is radians?
adj/opp
What is cotu?
-(sq.root2)/2 in Q3
What is sin(5pi/4) or What is cos(5pi/4)?
2cos2u - 1
What is cos(2u)?
cos2u - 1
What is -sin2u?
sq.root 3
What is cot(pi/6)?
secu
What is hyp/adj? or What is 1/cosu?
"1" in Q1.
What is tan(pi/4)?
cos2(2u) - sin2(2u)
What is cos(4u)?
sec2u - 1
What is tan2u?
The reference angle to 7pi/6.
What is pi/6?
cscu
What is hyp/opp? or What is 1/sinu?
"-1" in Q4.
What is tan(-pi/4) or What is tan(7pi/4)?