Please provide detailed explanation and solutions to the following. Please pay attention to the equations given do not write again accidentally a wrong equation. I would rather for it to be written instead of typed because typing functions is confusing. Thank you

Find the equations of the planes tangent to the following surfaces at the specied points: (a) The surface 2xy +m=."'Z = 5 at the point (1. 2. 0). (b) The surface 2 = 4cos{x y) + 1 at the point (, ,3). . Consider the function f(x_ y) = ln(1 + 2): +3!2 +y). (:1) Estimate f(0.1.0.2). (b) Approximate the change in 2 when (x, y) changes from (0,0) to (0.05.0.1)