Computer Science 1
Pgm05
Problem Solving and Program Design Using C++
Summer 2015
ax 2  bx  c  0 . In addition to asking the user for values for a, b,
2
and c, you will ask the user for a tolerance value to be used to determine when the discriminant, b  4ac , is “close
Write a program that will solve the quadratic equation
enough” to zero to establish that the equation has one double real root, and you will ask the user for the desired number
of decimals places for the answers. Given that the tolerance value has been given the name
then the equation has one double real root
x1 
x
toler , if b 2  4ac  toler ,
b
2
. If b  4ac  toler , then the equation has two real roots,
2a
 b  b 2  4ac
 b  b 2  4ac
2
and x2 
. If b  4ac  toler , then the equation has two complex roots,
2a
2a
b
c1 

2a
b 2  4ac
2a
b
i and c2 

2a
b 2  4ac
i.
2a
Sample Run Number 1:
Program to solve quadratic equations:
ax^2 + bx + c = 0
Enter a tolerance value: 0.000001
Enter the desired number of decimal places: 3
Enter values for a, b, and c: 1 2 3
The equation has two complex roots:
c1 = -1.000 + 1.414i
c2 = -1.000 - 1.414i
Hit enter to exit the program:
Sample Run Number 2:
Program to solve quadratic equations:
ax^2 + bx + c = 0
Enter a tolerance value: .00001
Enter the desired number of decimal places: 2
Enter values for a, b, and c: 1 -4.7 4.8
The equation has two real roots:
x1 = 3.20
x2 = 1.50
Hit enter to exit the program:
Sample Run Number 3:
Program to solve quadratic equations:
ax^2 + bx + c = 0
Enter a tolerance value: .0001
Enter the desired number of decimal places: 2
Enter values for a, b, and c: 1 -3 2.25
The equation has one real double root: 1.50
Hit enter to exit the program:
Target Due Date: On or before Tuesday, July 14, 2015.
NOTE: A sample executable, TaylorRPgm05.exe, has been place on the Z drive.