SCool Revision Summary
SCool Revision Summary
The Basics from GCSE
Use Pythagoras and Trigonometry in rightangled triangles
Use Sine and Cosine rules in nonrightangled triangles
Radians
2p radians = 360 degrees, arc length s = rq, area of a sector A =
Angles on a coordinate grid are measured anticlockwise from the +ve xaxis.
The trig. functions are positive in these zones: 
Use these zones to find the extra solutions to trig. equations. 
Solve trig equations by:
General solutions are found by adding: 2np or 360^{0} for sin and cos. np or 180^{0 }for tan Remember the period changes with multiples of q. Cos cq has period 
Graphs of sin, cos and tan
Identities (In order of usefulness)

tan q =

cos2 q + sin2 q = 1

sec x = , cosec x = and cot x = .
Double Angle Formulae

sin 2A = 2sin A cos A,

cos 2A = cos^{2} A  sin^{2} A = 1  2sin^{2} A = 2cos^{2} A  1
These came from the compound angle formulae:

sin (A + B) = sin A cos B + cos A sin B

sin (A  B) = sin A cos B  cos A sin B

cos (A + B) = cos A cos B  sin A sin B

cos (A  B) = cos A cos B + sin A sin B
R cos (q  a) is used to add sine and cosine functions together.
(i.e. acosq + bsinq = R cos (q  a)) and R and a are found by:

Expand the bracket

Match the question to the expansion

Find R and a using R = , and a =
Sometimes you may need the factor formulae (adding sines or cosines together) or the halfangle formulae when integrating.