i created a program in javascript that computes vector coordinates, everything was smooth since i have the correct formula, but when i try to conpute for the cosine of 143.1301 using Math.cos in javascript it returns 0.1864 instead of 0.7999 from the scientific calculator why is that? can anyone explain to me why? and also please give me the solution for this problem... thanks in advance... :) here;s a sample of my code

function cyltoxec(a)  
{
    ans = Math.cos(a);  
    return ans.toFixed(4);
}
var = x;
return cyltoxec(x);

i created a program in javascript that computes vector coordinates, everything was smooth since i have the correct formula, but when i try to conpute for the cosine of 143.1301 using Math.cos in javascript it returns 0.1864 instead of 0.7999 from the scientific calculator why is that? can anyone explain to me why? and also please give me the solution for this problem... thanks in advance... :) here;s a sample of my code

function cyltoxec(a)  
{
    ans = Math.cos(a);  
    return ans.toFixed(4);
}
var = x;
return cyltoxec(x);

• javascript

• 2 Welcome to Stackoverflow. Please use {} present on the editor window to format your code. You can always have a preview of what it looks like down under the editor window even before posting. – Mahesh Commented Aug 27, 2011 at 15:51
• 1 0.1864 is in radians, 0.8 is in degrees. – user555045 Commented Aug 27, 2011 at 15:52

2 Answers 2

Trigonometric functions in JavaScript (and indeed, in most mathematical parlance and programming) use radians as the angular unit, not degrees.

There are 2 * Pi radians in 360 Degrees. Thus, the cosine of a degrees is

Math.cos(a * Math.PI/180)

Math.cos expects its argument to be in radians, not degrees. Try Math.cos(a * Math.PI/180) instead.