MDME: MANUFACTURING, DESIGN, MECHANICAL ENGINEERING 

TRIGONOMETRY


Trigonometry relates the ratios of lengths and angles using special functions: sin(), cos(), tan(), etc.

Right Angle Triangles

A right angle triangle contains an angle of 90 degrees.

Type of OperationDefinition
sine A
cosine A
tangent A
Pythagorus c2 = a2 + b2
One way to remember this is SOH-CAH-TOA

Inverse Trig Functions (Finding the angle)

If sin(A) = a/c, then
A = sin-1(a/c)
or   asin(a/c)
or   arcsin(a/c)

Scalene Triangles

All other triangles (non right angle triangles) are called scalene triangles. The above simple rules do not apply to scalene triangles.
Take note of the labelling: Uppercase for angles ABC, lowercase for sides abc.


Type of OperationDefinitionYou must have...
Sine Rule
1 angle with opposite side +
1 other (side or angle)
Cosine Rule
(side)

1 angle with 2 adjacent sides
Cosine Rule
(angle)

3 sides


Questions:

Homework Assignment: 

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