sin x
tan x cos x
sin x
=
=
y
y
y cos x
The reason for this is from simple fraction division.
€
sin x
y
The y on the bottom of cos x is equivalent to
y
1
When dividing
€ the divisor upside-down, and multiply
€ by a fraction, you turn
So the equation becomes:
€
sin x 1
sin x
which can be written as
cos x y
y cos x
€