Oh joy. Oh yes. It’s another awful maths post, so feel free just to skip right over this. I only type these things up because it’s actually really good revision. It actively encourages me to think about the maths, and I’m likely to see it again when I log in. So without further adue:
Basic Functions:
y=sinx
y=cosx
y=tanx
cosecx=1/sinx
secx=1/cosx
cotx=1/tanx
P1 Identities
1) sinA/cosA = tanA
2) cos^2A + sin^2A = 1
P2 Extensions
Divide 2) by cos^2A
3) 1 + tan^2A = sec^2A
Divide 3) by sin^2A
4) cot^2A + 1 = cosec^2A
Further Identities
5) sin(A + – B) = sinAcosB + – sinBcosA
When A = B:
6) sin2A = 2sinAcosA
7) cos(A + – B) = cosAcosB – + sinAsinB (note the change of signs)
When A = B:
8) cos2A = cos^2A – sin^2A
Replace -sin^2A with cos^2 – 1:
9) cos2A = 2cos^2A – 1
Replace cos^2A with 1 – sin^2A
10) cos2A = 1 – 2sin^2A
11) tan(A + – B) = (tanA + – tanB)/(1 – + tanAtanB) (note the sign orders)
12) sin^2.1/2A = 1/2(1 – cosA)
13) cos^2.1/2A = 1/2(1 + cosA)
Okay, and believe it or not, that’s not everything ;_; – but I have to go to work now, so I’ll finish up later…
Hey thanx for that. Helped me too.
Hey thanx for that. Helped me too.