Find the Expression as the Sine or Cosine of an Angle

question 180

Multiple Choice

Find the expression as the sine or cosine of an angle.
$\cos 9 x \cos 5 y + \sin 9 x \sin 5 y$

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Definitions:

Positive Pole

In electrical terminology, the terminal of a battery or device from which current flows out, having a higher electrical potential.

Muscle End Plate

A specialized area of muscle fiber membrane where a motor neuron terminates and transmits nerve impulses to the muscle, leading to contraction.

Neurotransmitter-activated Ion Channels

Ion channels that open in response to the binding of a neurotransmitter, allowing ions to enter or exit the neuron and alter its electrical charge.

Myasthenia Gravis

Myasthenia Gravis is an autoimmune disorder characterized by weakness and rapid fatigue of any of the muscles under voluntary control, caused by a breakdown in communication between nerves and muscles.