Can someone please help me

Will give brainliest summations with algebraic expressions image shown

Find the gradient of f(x,y,z)equals=left parenthesis x squared plus y squared plus z squared right parenthesis superscript negative 1 divided by 2 baseline plus ln left parenthesis x right parenthesis x2+y2+z2−1/2+ln(xyz) at the point left parenthesis negative 2 comma 1 comma negative 2 right parenthesis(−2,1,−2).

For the following geometric sequence, find the recursive formula. {-80, 20, -5, } i need : ')