# Plane and Spherical Trigonometry, Surveying and Tables

Ginn & Company, 1897 - Logarithms

### Popular passages

Page 52 - ... cos y — sin x sin y tan a- + tan y 1 — tan x tan y sin (x — y) = sin x cos y — cos x...
Page 171 - The Celestial Equator, or Equinoctial, is the great circle in which the plane of the earth's equator produced intersects the surface of the celestial sphere.
Page 61 - The sides of a triangle are proportional to the sines of the opposite angles. If...
Page 141 - I. The sine of the middle part is equal to the product of the tangents of the adjacent parts.
Page 26 - Geometry that the area of a triangle is equal to one-half the product of the base by the altitude. Therefore, if a and b denote the legs of a right triangle, and F the area...
Page 63 - The bisector of an angle of a triangle divides the opposite side into segments proportional to the adjacent sides.
Page v - If the number is less than 1, make the characteristic of the logarithm negative, and one unit more than the number of zeros between the decimal point and the first significant figure of the given number.
Page 226 - ... is called the variation of the needle at that place, and is east or west, according as the north end of the needle lies on the east or west side of the true meridian.
Page 174 - Azimuth of a point in the celestial sphere is the angle at the zenith between the meridian of the observer and the vertical circle passing through the point; it may also be regarded as the arc of the horizon intercepted between those circles.
Page 30 - From the top of a hill the angles of depression of two successive milestones, on a straight level road leading to the hill, are observed to be 5° and 15°.