Consider a right triangle containing an angle θ. All such triangles are just scalar multiples of each other. Therefore the ratio of the adjacent side to the hypotenuse is a fixed value.
We'll call this ratio the cosine of θ. Similarly, we can define the sine of θ as the ratio of the opposite side to the hypotenuse
Now, we can show that
First we'll substitute
And by the Pythagorean Theorem
And so
Where's The Definition of Cosine and Sine?
ReplyDeleteIt's there .. it says that cosine of theta is defined as the ratio a / c, and sine is defined as the ratio of b / c
ReplyDeleteI guess it could've been a bit more explicit .. possibly put those two statements in their own stand-alone equations.
where was the word cosine drived from ??????????
ReplyDeleteThese rules are the base of trigonometry and without such rules one can not get good into this section.
ReplyDelete