# C2

- Created by: Kate Partridge
- Created on: 24-12-11 14:33

**C2 Revision Notes**

· The laws of logarithms:

logₐx+logₐy=logₐ(xy)

logₐx-logₐy=logₐ(x/y)

logₐxʲ=jlogₐx

logₐa=1, log₁₀10=1, etc.

· Arithmetic Progressions:

k=term

a=1^{st} term

d=difference of two terms

l=last term

s=sum of

· Geometric Progressions:

k=term

a=1^{st} term

r=ratio (the number each term is multiplied by to get the next term)

s=sum of terms

· A progression is arithmetic if the difference between each term is the same. A progression is geometric if the difference between each term is different

· Always work in radians for arc length and sector area questions

· Radians to degrees- divide by π and multiply by 180

· Degrees to radians- divide by 180 and multiply by π

· 2π=360

· S=rθ

where s=arc length of sector

r=radius

θ=angle (in radians)

· A=(1/2)r²

where a=area of sector

r=radius

θ=angle in radians

· Special angles:

sin30°=1/2

sin60°=√3/2

sin45°=1/√2

cos30°=√3/2

cos60°=1/2

cos45°=1/√2

tan30°=1/√3

tan60°=√3

tan45°=1

· The sine rule:

Where a, b and c are…

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