Any help would be appreciated!

theto 1 ) For the function b (x,g ) = arctan) when on wide "ai) compute the partial derivatives Of and, 26 9the to OX b, ) use part ( a) to write down a formula for do, the differential of the function + theta thety ( ) Find an equation for the tangent plane to 2 = 0 1xy ) at the point (2,1, 8(2, 1) ) d, ) use either part ( a) or part (b) to estimate the value of (1 - 10 , 2+ 10"18)