Answer:
x = cos(θ)
Step-by-step explanation:
The above relation is one that is usefully committed to memory. The mnemonic SOH CAH TOA can help you remember it, along with ...
y = sin(θ)
The x-value is adjacent to the central angle; the y-value is opposite. The hypotenuse of the relevant triangle in a unit circle is 1.
The x-value is ...
x = cos(θ)
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These relationships are necessary to convert from rectangular to polar coordinates and vice versa. They are also helpful when working vector problems.
