This is a free lesson from our course in Trigonometry This lesson introduces and walks you through the basics of trigonometric functions, with the help of several examples, practice questions with solution and video explanation by instructor in own hand writing. The trigonometric functions (also called circular functions) are functions of an angle. Trigonometric functions are commonly defined as ratios of two sides of a right triangle containing the angle or they can be also defined as the lengths of various line segments from a unit circle.There are six basic trigonometric functions i.e. sine, cosine, tangent, cosecant, secant and cotangent. (More text below video...)
Other useful lessons:
 Definitions of Trigonometric Functions The unit circle, Sine, and Cosine Graphs of Sine and Cosine Functions
(Continued from above) You�ll understand how you can use the ratios of side-length of right triangles to determine the measures of sides and angles. You�ll apply the Pythagorean Theorem, concepts of ratio and properties of sines, cosines, and tangents to solve the triangle, that is, to find unknown parts in terms of known parts. E.g. In a right triangle ABC, with sides a, b and c, you need to remember: Pythagorean theorem: a2 + b2 = c2
Sines: sin A = a/c, sin B = b/c
Cosines: cos A = b/c, cos B = a/c
Tangents: tan A = a/b, tan B = b/a
Now let's find solution of a problem where you don't know the hypotenuse but you do know the other two sides. You need to remember the Pythagorean Theorem to do. Apply it and that yields the hypotenuse. For example: if a = 10 and b = 24, then c2 = a2 + b2 = 102 + 242 = 100 + 576 = 676. The square root of 676 is 26, so c = 26.
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