1 THE UNIVERSITY OF ILLINOIS LIBRARY 5l0.2iz M264w t «EMAT! 0? UBSAiS]) • Return this book on or before the Latest Date stamped below. A charge is made on all overdue books. University of Illinois Library M32 Stewart's Educational Series. ‘WEINKLES’ IN ALGEBRA, ARITHMETIC, EUCLID, MECHANICS, CHEMISTRY, HEAT AND LIGHT, MAGNETISM AND ELECTRICITY, BEING FORMULAE, DEFINITIONS, LAWS AND PROPOSITIONS FOR THE USE OF LONDON MATRICULATION AND OTHER STUDENTS ARTHUR G. MADGE, B.A. \t LONDON: W. STEWART & CO., Ld., HOLBORN VIADUCT STEPS, E.C. $ig /(4J-/ZZ SI ••*«*»» PREFACE. This little book pretends to be nothing more than a summary of Formulae, &c., for the use of Matriculation students, who, after reading, require to remember accurately and thoroughly the Propositions, Theorems, &c., they have read. Each section should be revised frequently, and the book being so small, can easily be carried in one’s pocket and used whenever, amidst other work, there may be a few minutes' leisure. By using the book daily in this way, the student will soon thoroughly know the skeleton of his work, and then in his later revisions will be able, with his additional information, to clothe it. ARTHUR G. MADGE, B.A., Endowed School, Watford, Herts. CONTENTS. 44 Section I. Algebra, • Section II. Arithmetic, • Section III. Euclid, . • Section IV. Mechanics, • Section V. Chemistry, • Section VI. Heat and Light, • Section VII. Magnetism and Electricity WRINKLES’ IN ALGEBRA, ARITHMETIC, Ac. SECTION I. ALGEBRA. 1 . (a) (a + b ) 2 (fi) (« - 6 ) (y) (a + &) (ct-b) a 2 4 - '2ab + 6 2 . a 2 - lab + 6 2 . a 2 - h 2 . a 3 + 3a 2 6 + 3a6 2 + 6 3 . a 3 - 3a 2 6 + 3a6 2 - 6 3 . 9 (a + by (a - by 3. To square a trinomial such as (a + b - c), treat (a + b) as one term, and then square as in (1) (3. (a + b - c) 2 — {(a + b) - c} 2 = a 2 + ‘lab + b 2 - lac - 26c 4- c 2 . 4. To square a quantity with four terms as (a + 6 - c + d), bracket so as to reduce it to form of (1) /?. (a + b - c + cl) 2 = {(a + b) - (c - d)} 2 = a 2 4 lab +b 2 — 1 (ac + bc- ad - bd) + c 2 - led + d 2 . 5. Let n be any whole number, then / v a n -f b n is divisible by a + b when n is odd. [CLjTl. -tfi 7 v 7 a + b if a - b never. ( 0/71 ~ * s divisible by a + b when n is even. 'P' a n -b n ii a - b always. 6. When a n — b n is divided by a —b, all terms of quotient will be + as --— = a 3 + a 2 b 4- a6 2 + 6 3 . a-b 7. When a n - b n is divided by a + b, then the terms G ‘ WRINKLES ’ IN ALGEBRA, 8. a° = 1. 9. Let x 2 +px + q = o be taken as type of quadratic equation, then (a) a quadratic equation has two roots and only two. ( b ) the roots of the equation are :— i. li. -p.+ 9 \/(? - *) -i -Ai- *) iii. The sum of the roots = coefficient of second term with sign changed. iv. The product of the roots = the last term. 10. The equation to x 2 +px + q = 0 has its roots. (a) real and different when p 2 is greater than 4^/. (b) real and equal when p 2 is equal to 4 q. (c) impossible and different when p 2 is less than 4 q. 11. Arith. Prog. s = sum of terms, n = number of terms, a = first term, d — common difference, l = last term. Then (a) l = a + (n - 1 )d 08 )« = £ (a + l) substituting value of l in (/?) s = ~ {2a+ (n - 1)^7} A 12. Geom. Prog. s = sum of terms, a = first term, r = constant factor, n = number of terms. Then i. n th term = ar n ~ x a (r n - 1) a ( 1 - r n ) li. s = —^- —a or —A- r - l 1 - r iii. To sum a series of terms to infinity a s — 1 - r a + b 13. The Arith. mean between a and b is A ir Geom. ii J ab ARITHMETIC, EUCLID, MECHANICS, ETC. 7 SECTION II. ARITHMETIC. 1. Abstract numbers are numbers in general, "and have no reference to one thing more than another, as 9, 11. 2. Concrete numbers are applied to some particular object, as 9 cows, 11 horses. 3. A prime number is one that can only be divided by itself and unity without a remainder; and numbers are prime to each other when no number but unity will divide them without a remainder. 4. Composite numbers are such as are produced by the multiplication of two or more prime numbers. 5. To multiply by 5, 25, 125, 625, (a) To multiply by 5 add 1 cypher to the number and -=- by 2 (b) n 25 m 2 cyphers »» -f- u 4 (c) u 125 ii 3 n n -f- u 8 (d) n 625 n 4 a n t n 16 Similar rules can be found to multiply by 1*25, 62*5, 333J, &c. 6. To divide by 25, 125,