10) Find the limit, if it exists, or show that the limit does not exist.
Extracted text: 5-20 Find the limit, if it exists, or show that the limit does not exist. lim 5. (x, y)→(1, 2) (5.x³ – x²y²) 6. lim e *y cos(x + y) (x, y)→(1, – 1) x? + sin’y 7. lim 8. lim (x, y)→(0, 0) 2x² + y? 4 (х, у) — (0, 0) х* + Зу* ху сos y 6x'y 9. lim (х, у) — (0), 0) Зx?2 + y? 10. lim (х, у) — (0, 0) 2х*+y ху x² sin y 11. lim 12. lim (x, y)→(0, 0) Vx² + x² + y² (х, у) — (0, 0) х2+2у? x²ye" 13. lim 14. lim (x, y)→(0, 0) x* + 4y? (x, y)→(0, 0) x² + x4 4 x² + y? - 15. lim (х, у) — (0, 0) lim 16. ² + y² + 1 – 1 (х., у) —- (0, 0) х? + y 17. lim е *у sin(тz/2) (x, y, 2) →(3, 0, 1) x? + 2y? + 3z² lim 18. (x, y, z)→(0, 0, 0) x² + y² + z? ху + yz* + xz? lim (x, y, 2)→(0, 0, 0) x² + y² + z4 19. yz 20. lim (x, y, z)→(0, 0, 0) x² + 4y² + 9z²