Question

the language is c++

Goals: Developing problem-solving skills, declaring variables, multi-way branches, data validation. Problem: Astronomers have measured the magnitude (brightness) of a binary star as a function of time and found it to have periodicity (cycle) of 6.4 days. The magnitude varies as given below. from times t 0 days until t 0.9 days the magnitude is 2.5 from times t-0.9 days until t 2.3 days the magnitude may be calculated by the fomula 3.355- In(1.352+cos(x* (t - 0.9)0.7) from times t 2.3 days until t 4.4 days the magnitude is 2.5 from times 4.4days until t-5.2 days the magnitude may be calculated by the formula 3.598- In(1.998+cos(r *( t - 4.4)0.4)) from times-5.2 days until t-6.4 days the magnitude is 2.5 At 6.4 days the cycle begins again as if the time was 0 days. A graph for 2 cycles (12.8) days is given below. 4.4 42 4 3.8 3.6 34 32 3 2.8 26 2.4 8 10 12 14 Create a program will prompt the user to enter a time in days and calculate the magnitude of the binary star for that time. Your program should use a simple if to ensure that the entered time is valid (greater than or equal to 0) and prompt the user to re-enter if the entered time is invalid. Then use an if-elseif structure to determine the magnitude for the entered time. Your output should be similar to Output the days to 3 significant figures days the magnitude of the binary star is 15 "At and the magnitude to 5 significant figures. Hint: The fimod function will calculate the remainder of floating-point division.

Answer 1

ANSWER:

#include<iostream>
#include<cmath>
#include<iomanip>
using namespace std;
int main()
{
float days,angle,magnitude; //variables for storing number of days, the angle used in cosine and magnitude of brightness
cout<<"Enter the number of days: "; //Prompting the user to enter the number of days
cin>>days; //User entering the number of days
while(days<0.0) //if user enters a negative value
{ //Prompting him to enter the value again
cout<<"Enter a number greater than 0: ";
cin>>days;
}
float days2=fmod(days,6.4); //variable to store days%6.4 as cycle is of 6.4 days
if(days2<0.9) //If days are from 0 to 0.9
{
magnitude=2.5; //then magnitude = 2.5
}
else if(days2<2.3) //If days are from 0.9 to 2.3
{
angle=3.14*(days-0.9); //calculating angle to be used in cosine
angle=angle/0.7;
magnitude=3.355-(log(1.352+cos(angle))); //formula for magnitude
}
else if(days2<4.4) //If days are from 2.3 to 4.4
{
magnitude=2.5; //then magnitude is 2.5
}
else if(days2<5.2) //If days are from 4.4 to 5.2
{
angle=3.14*(days-4.4); //calculating angle to be used in cosine
angle=angle/0.4;
magnitude=3.598-(log(1.998+cos(angle))); //formula for magnitude
}
else //If days are from 5.2 to 6.4
{
magnitude=2.5; //then magnitude is 2.5
}
cout<<"At ";
cout<<setprecision(3)<<days; //setting precision of days to 3
cout<<" days the magnitude of the binary star is ";
cout<<setprecision(5)<<magnitude<<endl; //setting precision of magnitude to 5
return 0;
}

Output

Enter the number of days: -2.3 number greater than 0: 11.2 Enter a At 11.2 days the magnitude of the binary star is 3.5996 . Program finished with exit code 0 Press ENTER to exit console.