The 3 Pythagorean Identities:
The Pythagorean identities in trigonometry are the three identities that come from the Pythagorean theorem. Remember that the Pythagorean theorem states that the hypotenuse squared of a right triangle is the sum of the square of each of the other two sides. In the Pythagorean theorem, c stands for the hypotenuse, and a and b stand for the other two sides of the right triangle. From this theorem, three identities can be determined from substituting in sine and cosine. |
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example #1 : In a triangle ABC, with B As a right angle, suppose thAT sin(A) = 0.25
What is the cos(A)?
![Picture](/uploads/5/3/3/8/53384159/5068276.gif?250)
Step 1: Set up your equation
![Picture](/uploads/5/3/3/8/53384159/5837331.gif?1432773762)
Step 2: Show your work
![Picture](/uploads/5/3/3/8/53384159/6073187.gif?1432773839)
Step 3: Your final answer !
example brought to you by purplemath.com
example brought to you by purplemath.com