An Elementary Treatise on Plane and Spherical Trigonometry: With Their Applications to Navigation, Surveying, Heights and Distances, and Spherical Astronomy, and Particularly Adapted to Explaining the Construction of Bowditch's Navigator and the Nautical Almanac |
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Page 5
... included between 0 ° and 45 ° , it is evident that the last half of the above series is essentially a repetition of the first half , and is there- fore unnecessary . c . But as there is an infinite variety of values which an angle may ...
... included between 0 ° and 45 ° , it is evident that the last half of the above series is essentially a repetition of the first half , and is there- fore unnecessary . c . But as there is an infinite variety of values which an angle may ...
Page 10
... angle is equal to the perpen- dicular let fall from one extremity of the arc which measures it , in the circle whose ... included between the sine and the centre . Proof . Let ACB ( fig . 5 ) be the angle , and let the radius of the ...
... angle is equal to the perpen- dicular let fall from one extremity of the arc which measures it , in the circle whose ... included between the sine and the centre . Proof . Let ACB ( fig . 5 ) be the angle , and let the radius of the ...
Page 45
... included angle are given . [ B. , p . 43. ] Solution . Let the two sides a and b ( fig . 1 ) be given , and the included angle C ; to solve the triangle . First . To find the two unknown angles . Subtract the given angle C from 180 ...
... included angle are given . [ B. , p . 43. ] Solution . Let the two sides a and b ( fig . 1 ) be given , and the included angle C ; to solve the triangle . First . To find the two unknown angles . Subtract the given angle C from 180 ...
Page 46
... angles = { 100.56 9 ° 54 ' 39 " 0 ° 7 ' 21 " 2. Given two sides of a triangle equal to 10.121 and 15.421 , and the included angle equal to 41 ° 2 ' ; to solve the triangle . Ans . The other side = 10.236 The other angles = 40 ° 28 ' 28 ...
... angles = { 100.56 9 ° 54 ' 39 " 0 ° 7 ' 21 " 2. Given two sides of a triangle equal to 10.121 and 15.421 , and the included angle equal to 41 ° 2 ' ; to solve the triangle . Ans . The other side = 10.236 The other angles = 40 ° 28 ' 28 ...
Page 48
... included angle . 87. Corollary . The above proposition , when applied to the right triangle , becomes the Pythagorean proposition . For , if A is the right angle and a the hypothenuse , cos . A = 0 , by ( 66 ) , and ( 139 ) becomes a2 ...
... included angle . 87. Corollary . The above proposition , when applied to the right triangle , becomes the Pythagorean proposition . For , if A is the right angle and a the hypothenuse , cos . A = 0 , by ( 66 ) , and ( 139 ) becomes a2 ...
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Common terms and phrases
A₁ aberration acute adjacent Aldebaran ascension and declination azimuth celestial equator celestial sphere circle computed Corollary corr correct central altitude correction of Table corresponding cosec cosine cotan denote departure diff difference of latitude difference of longitude dist earth ecliptic equal to 90 formulas gives Greenwich Hence horizon horizontal parallax hour angle hypothenuse included angle interval mean meridian altitude method middle latitude miles moon moon's motion Napier's Rules Nautical Almanac Navigator obliquity observer at Boston obtuse opposite parallax perpendicular plane pole position prime vertical Problem Prop R₁ radius rhumb right ascension sailing Scholium secant second member semidiameter sideral sideral day solar Solution solve the triangle spherical right triangle spherical triangle star star's sun's tang tangent Theorem transit Trig true latitude vernal equinox vertical whence zenith
Popular passages
Page 44 - In any plane triangle, the sum of any two sides is to their difference as the tangent of half the sum of the opposite angles is to the tangent of half their difference.
Page 125 - II. The sine of the middle part is equal to the product of the cosines of the opposite parts.
Page 109 - PROBLEM III. To find the height of an INACCESSIBLE OBJECT above a HORIZONTAL PLANE. 11. TAKE TWO STATIONS IN A VERTICAL PLANE PASSING THROUGH THE TOP OF THE OBJECT, MEASURE THE DISTANCE FROM ONE STATION TO THE OTHER, AND THE ANGLE OF ELEVATION AT EACH. If the base AB (Fig.
Page 41 - To find a side, work the following proportion: — as the sine of the angle opposite the given side is to the sine of the angle opposite the required side, so is the given side to the required side.
Page 243 - Solar Day is the interval of time between two successive transits of the sun over the same meridian ; and the hour angle of the sun is called Solar Time. This is the most natural and direct measure of time. But the intervals between the successive returns of the sun to the meridian are not exactly equal, but depend upon the variable> motion of the sun in right ascension. - The want of uniformity in the sun's motion in right ascension arises from two different causes ; one, that the sun does not move...
Page 117 - A spherical triangle is a portion of the surface of a sphere, bounded by three arcs of great circles.
Page 125 - NAPIER'S CIRCULAR PARTS. Thus, in the spherical triangle A. BC, right-angled at C, the circular parts are p, b, and the complements of h, A, and B. 167. When any one of the five parts is taken for the middle part, the two adjacent to it, one on either side, are called the adjacent parts, and the other two parts are called the opposite parts. Then, whatever be the middle part, we have as THE EULES OF NAPIER.
Page 163 - The cosine of half the sum of two sides of a spherical triangle is to the cosine of half their difference as the cotangent of half the included angle is to the tangent of half the sum of the other two angles. The sine of half the sum of two sides of a spherical...
Page 99 - Now the sum of the areas of the triangles is the area of the polygon, and the sum of the angles of the triangles is the sum of the angles of the polygon.
Page 299 - Twilight begins and ends when the sun is about 18° below the horizon.