MACHINE SHOP CALCULATION - OD1640 - LESSON 2/TASK 3
using tables 6 and 7 on pages 59 and 60 to find the angle of
the
corresponding function, as explained in the following two paragraphs.
b.
When the heading is at the top of the column, the number of degrees is
found at the top of the page, and the number of minutes will be in the
extreme left-hand column. In this case, the angle of the sine of .69466 is
44,, 0'.
c.
When the beading is at the bottom of the column, the number of degrees
is found at the bottom of the page, and the number of minutes will be in the
extreme right-hand column. NOTE: The following summary is provided to help
in locating the value of functions in the trigonometric tables.
This
summary shows how the functions of an angle change in value for angles from
0,, to 90,,. Notice that as the angle for sine increases from 0,, to 90,,, its
value also increases from zero to 1.0000. As the angle for cosine increases
from 0,, to 90,,, its value decreases from 1.000 to zero. As the angle for
tangent increases from 0,, to 90,,, its value increases from zero to infinity.
And, as the angle for cotangent increases from 0,, to 90,,, its value
decreases from infinity to zero.
EXAMPLE
Find the value of angle A when sin A = .96923.
SOLUTION
By referring to the preceding summary, it is seen that angle A must be
greater than 45,, and closer to 90,,. Therefore, examining the columns with
the sine heading at the bottom discloses the number
65
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