1 1 z¹(x)= ----------------- * 3tg²(x²/3-y/6) * ------------------- * (2x/3) tg³(x²/3-y/6) cos²(x²/3-y/6) 1 1 z¹(y)=---------------- * 3tg²(x²/3-y/6) * ------------------- *(-1/6) tg³(x²/3-y/6) cos²(x²/3-y/6)