Double Angle Formulae What are the double angle formulae? The double angle formulae are derived from the 'A+B' versions of the compound angle formulae: Exam Tip The double angle formulae are...
Compound Angle Formulae What are the compound angle formulae? There are six compound angle formulae (also known as addition formulae), two each for sin, cos and tan: For sin the +/- sign on the lef...
Inverse Trig Functions What are arcsin, arccos and arctan? These functions are the inverse functions of sin, cos and tan sin (arcsin x) = x cos (arccos x) = x tan (arctan x) = x The domains of sin,...
Trigonometry - Further Identities What identities do I need to know with secant, cosecant, and cotangent? There are two identities with sec, cosec and cot that you need to know and be able to use: ...
Reciprocal Trig Functions - Graphs What does the graph of the sec look like? The graph of y = secx looks like this: y-axis is a line of symmetry has period (ie repeats every) 360° or 2π radians ver...
Reciprocal Trig Functions - Definitions What are the reciprocal trigonometric functions? There are three reciprocal trig functions corresponding to the three regular trig functions Cotangent can al...
Small Angle Approximations Small angle approximations When an angle measured in radians is very small, you can approximate the value using small angle approximations These only apply when angles ar...
Trigonometry Exact Values Exact values In trigonometry some values of sin, cos and tan are “nice” For example sin 30° = ½, tan 45° = 1 We can find those associated with the angles 30°, 45° and 60° ...
Radian Measure Radian measure Radians are an alternative to degrees for measuring angles 1 radian is the angle in a sector of radius 1 and arc length 1 Radians are normally quoted in terms of π Thi...
