Elements of Plane and Spherical Trigonometry |
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Page 135
... hour of 12 were marked at the equator , both upon that meridian and the oppo- site one , and all the rest of the ... line of the dial , when it fell upon the like hour circle of the sphere . If the plane which intersects the sphere be ...
... hour of 12 were marked at the equator , both upon that meridian and the oppo- site one , and all the rest of the ... line of the dial , when it fell upon the like hour circle of the sphere . If the plane which intersects the sphere be ...
Page 136
... hour circles , obtain the hour lines for every variety of dial . And since the earth it- self compared with its distance from the sun , may , in reference to this branch of inquiry , be regarded as a point , if a small sphere of glass ...
... hour circles , obtain the hour lines for every variety of dial . And since the earth it- self compared with its distance from the sun , may , in reference to this branch of inquiry , be regarded as a point , if a small sphere of glass ...
Page 137
... hour line of 12 . 13. Those meridians passing through the style , which make angles of 15 ° , 30 ° , 45 ° , & c . with the meridian of the place ( marking the hour line of 12 ) are called hour circles , and their intersections with the ...
... hour line of 12 . 13. Those meridians passing through the style , which make angles of 15 ° , 30 ° , 45 ° , & c . with the meridian of the place ( marking the hour line of 12 ) are called hour circles , and their intersections with the ...
Page 138
... hour line to the meri- dian . Now , we may regard the dial whose plane coincides with MaT , as a vertical or erect dial at the place whose zenith is м , where м and z are on the same meridian , and , of course , reckon the hours alike ...
... hour line to the meri- dian . Now , we may regard the dial whose plane coincides with MaT , as a vertical or erect dial at the place whose zenith is м , where м and z are on the same meridian , and , of course , reckon the hours alike ...
Page 139
... hour line to the meridian : the first term is constant ; the second has a constant coefficient , to the variable quantity cot P , which undergoing all its changes of General Problem . 139.
... hour line to the meridian : the first term is constant ; the second has a constant coefficient , to the variable quantity cot P , which undergoing all its changes of General Problem . 139.
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Common terms and phrases
altitude angled spherical triangle axis azimuth base becomes bisect centre chap chord circle circle of latitude computation consequently cos² cosec cosine cotangent declination deduced determine dial diameter difference distance draw earth ecliptic equa equal equation Example find the rest formulæ given side h cos h half Hence horizon hour angle hypoth hypothenuse intersecting latitude logarithmic longitude measured meridian oblique opposite angle parallel perpendicular plane angles plane triangle pole problem prop quadrant radius rectangle right angled spherical right angled triangle right ascension right line secant sin a sin sin² sine solid angle sphere spherical excess spherical trigonometry star substyle sun's supposed surface tan² tangent theorem three angles three sides tion triangle ABC values versed sine versin vertical angle whence yards zenith
Popular passages
Page 4 - 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 248 - SCIENTIFIC DIALOGUES ; intended for the Instruction and Entertainment of Young People ; in which the first principles of Natural and Experimental Philosophy are fully explained, by the Rev.
Page 225 - ... third of the excess of the sum of its three angles above two right angles...
Page 19 - In any plane triangle, as twice the rectangle under any two sides is to the difference of the sum of the squares of those two sides and the square of the base, so is the radius to the cosine of the angle contained by the two sides.
Page 30 - TO THEIR DIFFERENCE ; So IS THE TANGENT OF HALF THE SUM OF THE OPPOSITE ANGLES', To THE TANGENT OF HALF THEIR DIFFERENCE.
Page 249 - OSTELL'S NEW GENERAL ATLAS; containing distinct Maps of all the principal States and Kingdoms throughout the World...
Page 34 - Call any one of the sides radius, and write upon it the word radius ; observe whether the other sides become sines, tangents, or secants, and write those words upon them accordingly. Call the word written upon each side the name of each side ; then say, As the name of the given side, Is to the given side ; So is the name of the required side, To the required side.
Page 69 - Being on a horizontal plane, and wanting to ascertain the height of a tower, standing on the top of an inaccessible hill, there were measured, the angle of elevation of the top of the hill 40°, and of the top of the tower 51° ; then measuring in a direct line 180 feet farther from the hill, the angle of elevation of the top of the tower was 33° 45' ; required the height of the tower.
Page 18 - AC, (Fig. 25.) is to their difference ; as the tangent of half the sum of the angles ACB and ABC, to the tangent of half their difference.
Page 83 - A cos 6 = cos a cos c + sin a sin c cos B cos c = cos a cos 6 + sin a sin 6 cos C Law of Cosines for Angles cos A = — cos B...