Your lab instructor will solve the following problems: Problem 1: Let z = cos(x+ 2y) , x =uv, and y = uv . Find and IN duov Problem 2: Let z = f(x, y) and y = g(x) . Show that d2 z azz N z dx 2 2x 2 + Oxdy 8 (x ) + Ov2 ( 8' ( x ) ) 2 4 -8" (x ) Problem 3: If y = 3f(x+t)-2g(x-t) , find y,, and yxx. Problem 4: Find and where z - arctan z = x+ y . Exercises