Using the unit circle, determine the value of cos(945°).

Using the periodic property of cos function, you can evaluate the value of cos(945°).

The value of cos(945°) is given by:

A function returning to same value at regular intervals of specific length(called period of that function).

It is

Thus, we have:

Thus:

Note that wherever i have used , it refers to (in degrees).

Thus, the value of cos(945°) is given by:

Learn more about periodicity of trigonometric functions here:

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Explanation:

The angle 945 degrees is not between 0 and 360. We need to adjust it so that we find a coterminal angle in this range. To do this, subtract off 360 repeatedly until we get into the right range

945 - 360 = 585, not in range, so subtract again

585 - 350 = 225, we're in range now

Since 945 and 225 are coterminal angles, this means cos(945) = cos(225)

From here, we use the unit circle. Your unit circle should show the angle 225 in quadrant 3, which is the lower left quadrant. The terminal point here at this angle is

The x coordinate of this terminal point is the value of cos(theta). Therefore   and this is also the value of cos(945) as well

where are the options?

step-by-step explanation:

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step-by-step explanation: