User defined cos function

I am having trouble with this problem. I have attached the assignment. My main problem is understanding what is being asked of me, I must have no idea. My professor told me I must use a loop because we don't know how many terms to use.

Here is what I have for the function (sorry for the cheesy comments we have too):

Code:

`float cosine(float rad, double a)`

{

//variable declarations

float cosineofradians;

float t2, t3, t4, t5;

t2 = (pow(rad, 2)/2.0);

t3 = (pow(rad, 4)/24.0);

t4 = (pow(rad, 6)/720.0);

t5 = (pow(rad, 8)/40320.0);

if(-t2<a||t2<a)

{

t2 = 0;

}

if(-t3<a||t3<a)

{

t3 = 0;

}

if(-t4<a||t4<a)

{

t4 = 0;

}

if(-t5<a||t5<a)

{

t5 = 0;

}

//calculating cosine of radians

cosineofradians = 1-t2+t3-t4+t5;

//returning the cos of radians

return cosineofradians;

}