Value of sin problem

I am new to this but let me see
are you sure the factorial works that way i have never tried to do that i remember writting a program once but didnt use it that way i think you will need to use a loop here for factorial
i am not sure
cause the error u get says it take only one argument
also try changing float to double since you are using power fucntions
and if you are sure factorial fuction works than do inform me i will check it for my self and let you know

I'm not really sure if the factorial works. That was one part that I thought might be wrong. I have been drawing a blank on how to make the factorial work for a while, even though I did one like a month ago.

ok so lets work on the factorial thing
first of all does the question says you need to use the while fuctions for factorials

No. I can use any function for the factorial.

not to sound rude but i think the equation that you have written is also wrong since you are suppose to add the previous one and you are not doing so for instance when you are adding previous one with the new number
you type

sum= sum + some new number

and also did you notice in the question sign are alternative one is +ve and the other is -ve
yo will have to deal with that too

also in the calculation line sine is calculated from x and n but the variable x never has any value assigned to it.

Ok I will look at that stuff. In case this helps, this is the actual problem that I'm using and trying to solve.
The value of sin(x) can be approximated by using the formula:
sin(x) = x −
x3
3!
+
x5
5!
−
x7
7!
+
x9
9!
· · ·
where x is an angle in radians. Using the formula, approximate the value of the
sine of an angle (in degrees) entered by the user by calculating the first 15 terms
of the series. The program should allow the user to repeatedly enter angles and
then display the sine, until the value 0 is entered. Here is the general outline
for the program:
1 read in a new value for angle
2 while(angle != 0){
3 convert angle to radians (multiply angle by PI/180)
4 sine = 0
5 n = 1
6 while(n ≤ 15) {
7 calculate next term of series and add it to/subtract it from sine
8 increment n
9 }
10 display sine
11 read in a new value for angle
12 }
Here is an example run of the program:
Enter an angle in degrees (0 quits): 30
sin(30) = 0.5
Enter an angle in degrees (0 quits): 45
sin(45) = 0.707106
Enter an angle in degrees (0 quits): 90
sin(30) = 1
Enter an angle in degrees (0 quits): 15
sin(30) = 0.258819
Enter an angle in degrees (0 quits): 60
sin(30) = 0.866025
Enter an angle in degrees (0 quits): 0

I finally have the program able to read out what sin equals. The problem is the it is giving me the wrong number. I have a feeling it is because of the "n" in the equation needs to be the factorial here. Here is what I have now:

ok first things first why dont you try writing the program only first for only one sine data once you get the correct answer than we can include the while loop that says while(x !=0}
ok try only for one sine value
and also u are making a mistake in this form

//priming
...............
while{x !=0)



//priming
...............
}
the dotted things must be same which is not in your program

I don't understand what you mean with the //priming thing. When I try to compile this one it only lets me find one sine, instead of going until 0 is entered like it is supposed to. Here is what I have now though:

BY priming i mean that what ever you type for getting the value for of sine

for instance

cin>>x
while(cin !=0)
{




cin>>x
}
this is what i mean tell me if you dont understand it
i will explaing it in detail

Ok I understand that now.

in the question that you have posted you are required to use to while statement
one you have used but the other one that requires you to use priming


cin>>x
while(cin !=0)
{




cin>>x
}

the underline must be same always what statement you write before while should be the same that you write before ending that while

Both ends are the same now. I'm still having trouble getting the right number though. It always gives me 1 as my sine.

tell me one thing when you compile this code of yours and run it without debugging
do you get a runtime error
because no where have you defined factorails value it is undefined

No, I don't get a runtime error. No matter what number I type in when I run it, it returns the value 1 for what sine equals. Unless I type 0 then it stops.

the reason is because you are closing your
FOR statement before that means by the time the factorial comes out of the loop it is already 15
but remember you are suppose to use each factorial like 3! should be 1*2*3
4!=1*2*3*4

but your for statement makes factorial already 15 before using it
and also dont make guesses use debugger to find the mistake that you are making in your program what goes wrong where using debugger and checking you local or auto windows

close your for statement where you close our while statement and also since you are not getting any result something is wrong with your equation

i will tell you one good trick
write the program again but this time only and only consider that you are finding the value of one sine for instance only with degree 30 only
since now you know how to do priming that you can do it in the end to enter multiple data until user enters 0
ok do it with only one dgree that is 30only

I changed the for loop to end at the end of the program, but it's still doing the same thing. When I compile and build it shows no errors or warnings. Let me know if I'm missing something about the debugging. I will try to do another program with only one.

once this work you can write add the
//priming
..........
while(cin !=0)
{

//priming
............
}

in the end once you do it it will be easy to add this and this thing makes your program get many data from the users unless he enters 0


you can mail me you program too if you want me to look at it
my e- mail is
xxx@xxx.com (E-mail removed by moderator)

i can write the program for you but you will learn more if you write it own your own it helps a lot and clear a lot of doubts and also it makes you learn the types of error or mistakes that you have done

its 6:12 AM here
i have to go to university at 8:00AM and i havent taken a nap so forgive me if i wasnt a help you can mail me if you want to with your doubt in this question bye

Yeah, I prefer to do the programs on my own and try to figure them out, but this one had stumpped me for a few days. I have been slowly realizing stuff and piecing them together. The help you have provided has been good also. I figured out one problem as to why I wasn't getting the right number. I plugged a wrong variable into the equation. The number is a little off but I think it has to do with how many digits I defined PI to. Thanks for all the help. I believe I can fine tune it and finish up from here hopefully. Here is the program now:

The problem lies in how you're defining the factorial function, or in this case not definining it. If you define the factorial function as a recursive function and write a loop to compute the sum over the odd powers of x as such then you're problem is finished.

#include <cstdlib>
#include <iostream>
#include <cmath>

#define PI 4.0*atan(1)

using namespace std;

//Define a function to recursively compute factorial n
int factorial(int);
//Since sin(x) is an infinite series define a function which computes a partial sum approximation to x
void Sin(double &x,int n);

int main(int argc, char *argv[])
{
double angle=0;
double x=0;
cout<<"Input an angle and I will compute the sine of that angle\n";
cin>>angle;

x=angle*(PI/180);

cout<<"sin("<<x<<") = ";
Sin(x,15);

system("PAUSE");
return EXIT_SUCCESS;
}
int factorial(int n)
{
if(n==0||n==1){
return 1;
}
else
return (n*factorial(n-1));
}
void Sin(double &x,int n)
{
double temp=0;
for(int i=0;i<n;i++){
temp+=(pow((double)(-1),(double)(i))*pow((double)(x),(double)(2*i+1)))/(double)(factorial(2*i+1));
}
cout<<temp<<endl;
}