1) y= sin^4 (5x-3tgx) / y'=? 2) {2x+y=3 {5x-z=4 {-3y-2z=-5
1 2 {2x+y=3⇒y=3-2x {5x-z=4⇒z=5x-4 {-3y-2z=-5 -3(3-2x)-2(5x-4)=-5 -9+6x-10x+8=-5 -4x=-5+1 -4x=-4 x=1 y=3-2=1 z=5-4=1 (1;1;1)