## An Elementary Treatise on the Geometrical and Algebraical Investigation of Maxima and Minima: Being the Substance of a Course of Lectures Delivered Conformably to the Will of Lady Sadler : to which is Added A Selection of Propositions Deducible from Euclid's Elements |

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Page 287

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**rhombs**, which form the solid angle at P , is equal to the solid space , which they add by their junction ; and the capacity of the solid so formed is equal to that of the prism . PROP . VII . 14. Problem . To determine when the solid ... Page 288

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**rhombs**which contain the solid angle , when the surface of the figure is a minimum . For , join L , I ; let APBQ be any other**rhomb**passing through A and B ; and , first , let it meet CF , in a point Q , which lies between C and L. From ... Page 289

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**rhomb**ML is greater than the**rhomb**PQ , and exceeds it by the difference of the two rect- angles AB , LI , and AB , IQ ; i . e . by a rectangle which has AB for its altitude , and the excess of IL above IQ for its base ; and , because ... Page 290

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**rhomb**ML above the**rhomb**PQ ; therefore the**rhomb**ML , together with the two trapeziums LE , LG , is less than the**rhomb**PQ , together with the two trapeziums QE , QG . If , now , a similar construction be made at D , and at the angle ... Page 291

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**rhomb**; but the angle ARI is equal to the angle BLC , the two tri- angles ARI , BLC having been shewn to be similar ; also , since ( E. 8. 1. ) the two triangles ALC , BLC , are equal , the angle ALC is equal to BLC , and is , therefore ...### Other editions - View all

An Elementary Treatise on the Geometrical and Algebraical Investigation of ... Daniel Cresswell No preview available - 2016 |

An Elementary Treatise on the Geometrical and Algebraical Investigation of ... D. Cresswell No preview available - 2015 |

An Elementary Treatise on the Geometrical and Algebraical Investigation of ... D 1776-1844 Cresswell No preview available - 2015 |

### Common terms and phrases

ABCD aggregate Algebra altitude angle equal apparent magnitude base Binomial Theorem bisected chord circumference coefficients Cx² derivative describe a circle diameter divided double draw a straight equal perimeter equation equilateral triangle Euclid Euclid's Elements find a point finite straight line function Geometry given angle given circle given finite straight given point given ratio given straight line given triangle greater ratio greatest hypotenuse inscribed isosceles triangle less Let ABC lines be drawn magnitudes MAXIMA AND MINIMA maximum minimum number of sides parallel parallelepiped parallelogram plane prism produced PROP proposition quadrilateral rectilineal figure rectangle contained regular polygon rhomb right angles right-angled triangle scalene triangle SCHOLIUM sector segment shewn square straight line drawn straight line joining subtended tangent Theorem trapezium triangle ABC variable quantity velocity vertex vertical angle wherefore

### Popular passages

Page 81 - If two triangles have one angle of the one equal to one angle of the other and the sides about these equal angles proportional, the triangles are similar.

Page 83 - The areas of two triangles which have an angle of the one equal to an angle of the other are to each other as the products of the sides including the equal angles. D c A' D' Hyp. In triangles ABC and A'B'C', ZA = ZA'. To prove AABC = ABxAC. A A'B'C' A'B'xA'C' Proof. Draw the altitudes BD and B'D'.

Page 56 - If a straight line be bisected, and produced to any point ; the rectangle contained by the whole line thus produced, and the part of it produced, together with the square...

Page 36 - In every triangle, the square of the side subtending any of the acute angles is less than the squares of the sides containing that angle by twice the rectangle contained by either of these sides, and the straight line intercepted between the perpendicular let fall upon it from the opposite angle, and the acute angle. Let ABC be any triangle, and the angle at B one of its acute angles, and upon BC, one of the sides containing it, let fall the perpendicular...

Page 32 - If there be two straight lines, one of which is divided into any number of parts, the rectangle contained by the two straight lines is equal to the rectangles contained by the undivided line, and the several parts of the divided line.

Page 85 - Divide a straight line into two parts such that the rectangle contained by the whole line and one of the parts shall be equal to the square on the other part.

Page 12 - If two triangles have the three angles of one equal to the three angles of the other, each to each, do you think the two triangles are necessarily alike in every respect ? 5.

Page 16 - If two triangles have two angles of the one equal to two angles of the other, each to each, and one side equal to one side, viz.

Page 154 - Iff a straight line be divided into any two parts, four times the rectangle contained by the whole line, and one of the parts, together with the square of the other part, is equal to the square of the straight line which is made up of the whole and that part.

Page 22 - If from the right angle of a right-angled triangle, two straight lines be drawn, one perpendicular to the base, and the other bisecting it, they will contain an angle equal to the difference of the two acute angles of the triangle.