客观c cos sin返回不同

Question

我需要你的OS开发帮助。我有C＃应用程序，我转换为Objective-C。 iOS返回不同的结果：

iOS中的结果：
GetHeading y：-0.000048
GetHeading x：-0.000087

iOS源代码：

double rlatitude1 = [self toRadians:startLocation.latitude];
double rlongitude1 = [self  toRadians:startLocation.longitude];
double rlatitude2 = [self toRadians:endLocation.latitude];
double rlongitude2 = [self toRadians:endLocation.longitude];
double y = sin(rlongitude2- rlongitude1) * cos(rlatitude2);
NSLog([NSString stringWithFormat:@"GetHeading y: %f",y]);

double x = cos(rlatitude1) * sin(rlatitude2) -  sin(rlatitude1) * cos(rlatitude2) * cos(rlongitude2 - rlongitude1);
NSLog([NSString stringWithFormat:@"GetHeading x: %f",x]);

iOS toRadiansCode：

+(double) toRadians:(double) degree
{
    double retVal = (degree * 0.0174532925);
    NSLog([NSString stringWithFormat:@"toRadians: %f",retVal]);
    return retVal;
}