Page 37 - Trigonometry

Example 11:

The diagram on the left shows a

2D vector rotated through an

angle θ. Rotation can be
represented by the action of a

2 × 2 matrix acting on a vector,

for example,

′ cos( ) −sin( )
( ) = ( ) ( )
′ sin( ) cos( )

The matrix operates on a vector to produce a rotated

vector. Consider the triangle
shown in the diagram on the

left. Rotate this triangle

o
through an angle of 27.5
around the origin. Start with

A we can see this has a

coordinate value of (2, 2),
therefore,

′ cos(27.5) −sin(27.5) 2
( ) = ( ) ( )
′ sin(27.5) cos(27.5) 2

This operation can be performed on your fx calculator,
first set up the Matrix A as a 2 × 2 with the keystrokes,

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