3. (6 pts) Find the equation of the tangent plane to at the point P= (0, 1, 1). z = e+y-1 cos(x + y-1) SQ dx = 2x. ex+y+ Cos(x" ty = 1) + ex+ (-4x Sin (x+y-1)) (x244-1) = 2xe" = 2xe (x+y-1) at p = (0,131) 28 dy = 0 = . Cos (x" ty 1) - 4x.ex++4+1). Sin (x^ty -1) "I cos(x" ty-1) - 2sin(x"+y-1)] exty- Cos (x+y-1) + ex+y-! 2y. Sin (x" ty+1) = ex+4-1 [ cos(x" + y-1) + 2y Sin (x + y+)]. at p = (0,111) = 1. T 1] = 1 z = 1. cos(0)=1 Tangent equation= dz 28 dx (x-0) + 3 (y-1) + = 0 + (y-1) +1 = y