MACHINE SHOP CALCULATION - OD1640 - LESSON 2/TASK 3
The trigonometric functions discussed here will be limited to the
sine, cosine, tangent, and cotangent, since practically every common shop
problem in trigonometry can be solved by means of these functions.
values of the trigonometric functions in terms of the names of the sides
should be learned. To assist in learning these functions, use the example
Using the lettered and named sides of the triangle (figure 12 on the
previous page), write the ratios for sin A, cos A, tan A, cot A, sin B, cos
B, tan B, and cot B.
sin A = a/c; cos A = b/c; sin B = b/c;
cos B = a/c; and tan A = a/b; cot A = b/a;
tan B = b/a; cot B = a/b.
sin A = cos B and cos A = sin B
tan A = cot B and cot A = tan B
A trigonometric function expresses the value of an angle in terms of
the sides of the right triangle containing that angle.
For instance, the
value of angle A in figure 13 on the following page may be expressed as:
Thus, if the function and the dimension of one of the sides of that function
ratio are known, then the dimension of the other side can be found.