Finite difference discretization of elliptic equations: Fd Formulas and Multidimensional problems Lecture 4￾✂✁☎✄✆✁✞✝✠✟☛✡☞✁✍✌✎✟✑✏✒✟✓✄✕✔✑✟☛✡☞✁☎✖✗✔✑✏✒✟✘✝✗✁☎✙✛✚✜✝✗✁✣✢✤✄ ✢✤✥✧✦✩★☎★☎✁☎✪✫✝✗✁✣✔✬✦✧✭✯✮✎✚✜✝✗✁✣✢✤✄✕✖✜✰✱￾✩✡ ￾✫✢✲✏✴✳✵✮✕★✶✚✷✖✸✚✷✄✺✹ ✻✼✮✕★✞✝✗✁✣✹✫✁✣✳✽✟✾✄✕✖✴✁✣✢✤✄✎✚✷★✧✿❀✏✒✢✤❁✕★✣✟✓✳❂✖ ❃❄✟✓✔✘✝✗✮✺✏✒✟❆❅