hp40g+.book Page 13 Friday, December 9, 2005 1:03 AM

Exercise 7

so, b3 = 999 ⋅ (c3 b3) + 1 , or b3 ⋅ 1000 + c3 (–999) = 1

The calculator is not needed for finding the general solution to equation [1].

We started with b3 x + c3 y = 1

and have established that b3 ⋅ 1000 + c3 (–999) = 1 . So, by subtraction we have:

b3 ⋅ (x – 1000) + c3 ⋅ (y + 999) = 0 or b3 ⋅ (x – 1000) = c3⋅ (y + 999)

According to Gauss’s Theorem, c3 is prime with b3 , so c3 is a divisor of (x – 1000) .

Hence there exists k Z such that: (x – 1000) = k c3

and

–(y+ 999) = k b3

Solving for x and y, we get:

x = 1000 + k c3

and

y= – 999 – k b3

for k Z .

This gives us:

b3 x + c3 y = b3 ⋅ 1000 + c3 (–999) = 1

The general solution for all k Z is therefore:

x= 1000 + k c3

y= – 999 – k b3

Let m be a point on the circle C of center O and radius 1. Consider the image M of m defined on their affixes by the

1

z

2

Z . When m moves on

transformation F : z >--

 

2

 

 

 

Step-by-Step Examples

16-13