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Without using a calculator, find the six trigonometric functions of 15º and 75º.
Solution:
Is it possible to find the six trigonometric functions for 15º and 75º without using a calculator? Well, we know the six trigonometric functions for the special angles such as 0º, 30º, 45º, 60º, and 90º. I am strongly advice that you must remember the trigonometric functions of special angles because you will use those later for proving of trigonometric identities, problem solving, and taking higher math subjects as well. Let's recall the six trigonometric functions of the special angles as follows
For 0º
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For 30º
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For 45º
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For 60º
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| Photo by Math Principles in Everyday Life |
For 90º
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| Photo by Math Principles in Everyday Life |
Therefore, using the Sum and Difference of Two Angles Formula, we have
