http://mathdl.maa.org/mathDL/46/?pa=content&sa=viewDocu - PowerPoint Presentation

Slide1

http://mathdl.maa.org/mathDL/46/?pa=content&sa=viewDocument&nodeId=2591&bodyId=3599Slide2
Slide3

The invention of the = sign

Robert

Recorde

1550Slide4

The invention of the = sign

Robert

Recorde

1550Slide5

The first equations ever written in English

14

x

+ 15 = 71

,

solution is

4

.Slide6

Recorde

explains subtraction

u

sing a poemSlide7
Slide8

http://mathdl.maa.org/mathDL/46/?pa=content&sa=viewDocument&nodeId=2591&bodyId=3599Slide9

The first equations ever written in English

Robert

Recorde

in

The Whetstone of Witte

1557

.

The equation in modern terms, by 14

x + 15 = 71

, whose solution is 4

.Slide10

Recorde

introduces for the first time, the "equal" sign.  He explains that he picked two parallel lines to represent this concept

 "because no two things can be more equal."Slide11
Slide12

n

English:

The first equation ever written, by

Robert Recorde

in his treatise

The Whetstone of Witte

, in 1557. The equation is represented, in modern terms, by 14x + 15 = 71, and its solution is 4.Slide13

The Whetstone of Witte is the shortened title of

Robert

Recorde

's

mathematics

book published in 1557. The full title being, The Whetstone of Witte,

whiche is the

seconde parte of

Arithmeteke: containing the extraction of rootes

; the

cossike

practise

, with the rule of equation; and the

workes

of

Surde Nombers

, the book covers topics including whole numbers, the extraction of roots and irrational numbers.

The work is notable for containing the first recorded use of the

equals sign

and also the first book in English to use the

plus and minus signs

. However,

exponentiation

was represented by a cumbersome form of mathematical notation in which

indices

and

surds

were represented by their

prime factors

(see

Prime factor exponent notation

).Slide14

The Whetstone of Witte is the shortened title of

Robert

Recorde

's

mathematics

book published in 1557. The full title being, The Whetstone of Witte,

whiche

is the

seconde parte of Arithmeteke

: containing the extraction of

rootes

; the

cossike

practise

, with the rule of equation; and the

workes of Surde

Nombers

, the book covers topics including whole numbers, the extraction of roots and irrational numbers.

The work is notable for containing the first recorded use of the

equals sign

and also the first book in English to use the

plus and minus signs

. However,

exponentiation

was represented by a cumbersome form of mathematical notation in which

indices

and

surds

were represented by their

prime factors

(see

Prime factor exponent notation

).Slide15
Slide16

http://nsm1.nsm.iup.edu/gsstoudt/history/images/witte.htmlSlide17

The invention of the = sign

Robert

Recorde

1550Slide18
Slide19

On 

this page

 (Sig. S, f.

i

v & f. 2 r),

Recorde

explains the notation for a unknown and its various powers.  Note that the owner of this particular copy wrote notes to help him understand the various names and abbreviations for the powers.

 Slide20

Recorde

explains subtraction of polynomials by use of a poem (

Sig. X, f. ii r

).Slide21

On this page (

Sig. Ff, f.

i

r

), we see

Recorde

introducing, for the first time, the "equal" sign.  He explains that he picked two parallel lines to represent this concept "because no two things can be more equal." He then gives various examples of the use of the equal sign in algebraic equations.Slide22

On these pages (

Sig. Ii, f. iv r

 & v and 

Sig.

Kk

, f.

i

r) is Recorde's attempt to design a real problem whose solution requires a quadratic equation.  This problem is entitled a "question of jorneying" and requires knowledge of the formula for the sum of an arithmetic progression.Slide23
Slide24

The Whetstone of Witte

by Robert Recorde (1557)

Recorde's algebra text where two equal parallel line segments as the symbol for equality was used for the first time: "bicause noe 2 thynges can be moare equalle".

http://nsm1.nsm.iup.edu/gsstoudt/history/images/witte.htmlSlide25

http://www.laputanlogic.com/articles/2004/04/13-0002.html

Robert Recorde