## An Introduction to the Theory and Practice of Plane and Spherical Trigonometry, and the Stereographic Projection of the Sphere: Including the Theory of Navigation ... |

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An Introduction to the Theory and Practice of Plane and Spherical ... Thomas Keith No preview available - 2016 |

### Common terms and phrases

_ sine acute adjacent angle altitude angle opposite Answer azimuth base centre circle co-tangent compasses complement construction cosec cosine degrees difference diﬁ'erence distance division draw ecliptic equation Euclid EXAMPLE ﬁgure ﬁnd the angle ﬁnding ﬁrst ﬁxed formula given angle given side greater Hence horizon hypothenuse latitude less line of numbers line of sines logarithm logarithmical sines longitude measure meridian moon’s natural number Nautical Almanac North observed obtuse opposite angle parallax parallel perpendicular plane sailing plane triangle Plate pole primitive PROPOSITION quadrant Rad x sine radius radz rhumb line right ascension right-angled spherical triangle RULE scale of chords SCHOLIUM secant semi-tangents side AC sine of half SOLUTION species sphere spherical angle spherical triangle ABC star star’s subtract sun’s declination supplement tang tangent tangent of half three angles three sides Toﬁnd Trigonometry versed sine zenith

### Popular passages

Page 25 - The circumference of every circle is supposed to be divided into 360 equal parts, called degrees ; each degree into 60 equal parts, called minutes ; and each minute into 60 equal parts, called seconds.

Page 138 - Consequently, a line drawn from the vertex of an isosceles triangle to the middle of the base, bisects the vertical angle, and is perpendicular to the base.

Page 6 - And if the given number be a proper vulgar fraction ; subtract the logarithm of the denominator from the logarithm of the numerator, and the remainder will be the logarithm sought ; which, being that of a decimal fraction, must always have a negative index.

Page xxvi - A New Treatise on the Use of the Globes; or, a Philosophical View of the Earth and Heavens : comprehending an Account of the Figure, Magnitude, and Motion of the Earth : with the Natural Changes of its Surface, caused by Floods, Earthquakes, Ac.

Page 32 - The CO-SINE of an arc is the sine of the complement of that arc as L.

Page 31 - The sine, or right sine, of an arc, is the line drawn from one extremity of the arc, perpendicular to the diameter passing through the other extremity. Thus, BF is the sine of the arc AB, or of the arc BDE.

Page 242 - The HORIZON is a great circle which separates the visible half of the heavens from the invisible ; the earth being considered as a point in the centre of the sphere of the fixed stars.

Page 242 - ... ZENITH DISTANCE of any celestial object is the arc of a vertical circle, contained between the centre of that object and the zenith ; or it is what the altitude of the object wants of 90 degrees.

Page 199 - The sum of the two sides of a triangle is to their difference as the tangent of half the sum of the angles at the base is to the tangent of half their difference.

Page 32 - The SECANT of an arc, is a straight line drawn from the center, through one end of the arc, and extended to the tangent which is drawn from the other end.