8825. Value of variable 1
Find the value of the variable y for
a given real value of the variable x.
Input. One real number x.
Output. Print the value of the variable y rounded
to three decimal places.
|
Sample input |
Sample output |
|
1 |
7.286 |
SOLUTION
mathematics
Algorithm analysis
To solve
the problem, compute the value of the given expression.
Algorithm
implementation
Read the value of the variable x.
scanf("%lf", &x);
Compute the value
of the variable y.
y = x * x * x -
5 * x * x / 7 + 9 * x - 3 / x + 1;
Print the result
rounded to three decimal places.
printf("%.3lf\n", y);
Java implementation
import
java.util.*;
class
Main
{
public static void main(String[] args)
{
Scanner con = new Scanner(System.in);
double x = con.nextDouble();
double y = x * x * x - 5 * x * x / 7 + 9 * x - 3 / x + 1;
System.out.printf("%.3f",y);
con.close();
}
}
Java implementation – class MyDouble
import
java.util.*;
class
MyDouble
{
private double a;
MyDouble(double a)
{
this.a = a;
}
MyDouble Add(MyDouble b)
{
return new MyDouble(a + b.a);
}
MyDouble Add(double b)
{
return new MyDouble(a + b);
}
MyDouble Sub(MyDouble b)
{
return new MyDouble(a - b.a);
}
MyDouble Mult(MyDouble b)
{
return new MyDouble(a * b.a);
}
MyDouble Divide(MyDouble b)
{
return new MyDouble(a / b.a);
}
MyDouble Divide(double b)
{
return new MyDouble(a / b);
}
public String toString()
{
return String.format("%.3f", a);
}
}
public class Main
{
public static void main(String[] args)
{
Scanner con = new Scanner(System.in);
MyDouble x = new MyDouble(con.nextDouble());
MyDouble a = x.Mult(x).Mult(x); // x^3
MyDouble b = new MyDouble(5).Mult(x).Mult(x).Divide(7); //
5 * x * x / 7
MyDouble c = new MyDouble(9).Mult(x); // 9 * x
MyDouble d = new MyDouble(3).Divide(x); // 3 / x
MyDouble res = a.Sub(b).Add(c).Sub(d).Add(1);
System.out.println(res);
con.close();
}
}
Python implementation
Read the value of the variable x.
x = float(input())
Compute the value
of the variable y.
y = x * x * x - 5 * x * x / 7 + 9 * x - 3 / x + 1
Print the result.
print(y)