trigonometry angle transformation formulas memorization tricks?

I found this online somewhere. Hope it helps.

The Cos (X) is a bad ***.. he thinks only of himself.. so when it's Cos(A+B) it's CosACosB first!

then because he's a bad ***, he changes the sign on purpose, so it would be Cos(A+B) = CosACosB-SinASinB

the Sin (Y) is a cop :) so the cop is "positive" and he won't let go of the bad *** (from both sides, like with handcuffs)

so it would be like this:

Sin(A+B) = SinACosB+CosASinB, The Cos in Sin(A+-B) is B and then A (The X feels uncomfortable)

This part is my creation. May not be the best but o well. :p

Tan (Y/X) is cos and sin's shady mutual friend and its hard to tell his true motives.

You do know all tan ever thinks about is him and his friend 1.

Some days Tan can do the right thing and not change the signs if he is alone.

However other days when he and his friend 1 get together they will surround signs and cause trouble. If you divide Tan's good days (tanA + tanB)

by his bad (1(- or +) tanA.tanB) you see who he really is.

Trigonometry Tricks

cos(A) = 1/2 so A = pi/3 cos(pi/6) = sqrt(3)/2