## Source Code

```
#include <iostream>
#include <cmath> // include the cmath library for the sqrt() function
using namespace std;
int main()
{
double a, b, c; // Declare variables to hold the coefficients of the quadratic equation
double x1, x2; // Declare variables to hold the roots of the equation
cout << "Enter the coefficient of x^2: "; // Prompt the user to enter the coefficient of x^2
cin >> a; // Read the coefficient of x^2 from the standard input stream
cout << "Enter the coefficient of x: "; // Prompt the user to enter the coefficient of x
cin >> b; // Read the coefficient of x from the standard input stream
cout << "Enter the constant term: "; // Prompt the user to enter the constant term
cin >> c; // Read the constant term from the standard input stream
// Calculate the roots of the equation using the quadratic formula
x1 = (-b + sqrt(b*b - 4*a*c)) / (2*a);
x2 = (-b - sqrt(b*b - 4*a*c)) / (2*a);
cout << "The roots of the equation are: " << x1 << " and " << x2 << endl; // Print the roots
return 0;
}
```

## Code Explanation

This program declares three variables `a`

, `b`

, and `c`

of type `double`

to hold the coefficients of the quadratic equation, and two variables `x1`

and `x2`

of type `double`

to hold the roots of the equation. It then uses the `cout`

object to print prompts asking the user to enter the coefficients and the `cin`

object to read the coefficients from the standard input stream.

To find the roots of the equation, the program uses the quadratic formula:

`x = (-b +- sqrt(b^2 - 4ac)) / (2a)`

where `a`

, `b`

, and `c`

are the coefficients of the equation, and `x`

is the root. The `+`

and `-`

signs represent the two possible roots of the equation.

The program calculates the roots using the formula and stores them in the variables `x1`

## Explain (cmath)

`<cmath>`

is a header file in the C++ standard library that defines a set of mathematical functions and macros. It is part of the C++ Standard Template Library (STL) and is defined in the namespace `std`

.

The functions defined in `<cmath>`

are a subset of the C math library (`math.h`

) and provide a range of mathematical operations such as trigonometric functions, exponential and logarithmic functions, power and absolute value functions, and more.

Here are some examples of functions defined in `<cmath>`

:

`sqrt()`

: calculates the square root of a number`pow()`

: raises a number to a specified power`exp()`

: calculates the exponential of a number`log()`

: calculates the natural logarithm of a number`abs()`

: calculates the absolute value of a number`sin()`

: calculates the sine of an angle`cos()`

: calculates the cosine of an angle`tan()`

: calculates the tangent of an angle

To use the functions defined in `<cmath>`

, you need to include the header file in your C++ program using the `#include`

preprocessor directive:

`#include <cmath>`

You can then access the functions using the `std::`

namespace prefix, or by using the `using namespace std;`

directive.

Note: C++ Complete Examples

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