Cosine can be explained in different ways. The best explanation for why cosine start fraction 2 pi over 3 end fraction not-equals cosine start fraction 5 pi over 3 end fraction, is that;
- Cosine is negative in the second quadrant and positive in the fourth quadrant.
<h3>What Cosine is all about</h3>
Note that the sine of any angle in the second quadrant is said to range between 90 and 180 degrees and it is regarded as positive. But, if the cosine and tangent of any angle is said to be in this quadrant, it is regarded as negative.
The cosine function can be said to be positive only in the first and fourth quadrants. And the tangent function is known to be also positive in the first and third quadrants.
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