Massive site - lots of Trig/Trigonometry resources - all in very extreme detail.*4**4**1*BASIC TRIGONOMETRY*2*Definitions*4*Using Tan to find angle*4*Using Tan to find side*4*Using Sine to find angle*4*Using Sine to find side*4*Using Cos to find angle*4*Using Cos to find side*4*Which ratio*4*Finding the hypotenuse*1*FORMULAE*2*Trig refresher*4*sec, cosec and cot*4*Compound formulae*4*Double Angle*4*Half Angle*4*Product formulae*4*Multiple Angle*4*Algebra - Solving Trig equations*1*AREA OF A TRIANGLE, SINE RULE, COSINE RULE*2*Area of a triangle - derivation*4*Area of a triangle - example*4*Sine Rule - derivation*4*Sine Rule- Example*4*Cosine Rule - derivation*4*Cosine Rule- Examples*4*Sine and Cosine Rule- refresher*4*Which rule to use ? SSS, etc*1*COMPOUND FORMULAE (ADVANCED)*2*Deriving compound angle*4*Compound angle formulae - Examples*1*TRIG FAMILIES*2*Amplitude and Period definition*4*Click to see which quadrant an angle lies in - Excel (125 KB)*1*AMPLITUDE AND PHASE ANGLE*2*See how trig graphs are affected by a change in amplitude or phase angle - Excel (1737 KB)*1*RADIANS*2*Radians*4*Converting degrees to Radians*4*Exact values Radians and Degrees*4*Using exact values : Radians and Degrees*4*Conversion table*1*THE WAVE FUNCTION*2*Adding two waves*4*Subtracting two waves*4*Express in the form cos(x+a)*4*Express in the form sin(x-a)*4*Express in the form sin(x+a)*4*Multiple Angles*4*Maximum / Minimum Value*4*Sketching graphs*4*Solving equations*4**4*UK site but relevant to any pupils covering mathematics.*4**4* Extremely useful for teachers of Maths/Mathematics.