e^(ix) = cos(x) + i sin(x)

struct complex
{
    float real;
    float imag;
};

struct complex sum(struct complex t1, struct complex t2)
{
    struct complex t;
    t.real = t1.real + t2.real;
    t.imag = t1.imag + t2.imag;
    return t;
}

struct complex product(struct complex t1, struct complex t2)
{
    struct complex t;
    t.real = t1.real * t2.real - t1.imag * t2.imag;
    t.imag = t1.real * t2.imag + t1.imag * t2.real;
    return t;
}