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...)
(Continued from above) You’ll understand how
you can use the ratios of sidelength 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: a^{2} + b^{2}
= c^{2}
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
c^{2} = a^{2} + b^{2} = 10^{2} + 24^{2}
= 100 + 576 = 676. The square root of 676 is 26, so c = 26.
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