Compute the Gradient of the Function at the Given Point $$f ( x , y , z ) = \tan ^ { - 1 } \frac { 7 x } { 9 y + 3 z } , ( 9,0,0 )$$

question 130

Multiple Choice

Compute the gradient of the function at the given point.
- $$f ( x , y , z ) = \tan ^ { - 1 } \frac { 7 x } { 9 y + 3 z } , ( 9,0,0 )$$

• A)\({\nabla} f = \frac { 1 } { 7 } \mathrm { j } - \frac { 1 } { 21 } \mathbf { k }\)
• B) \({\nabla} f = - \frac { 1 } { 21 } j + \frac { 1 } { 7 } k\)
• C) \({\nabla} f = - \frac { 1 } { 7 } \mathbf { j } - \frac { 1 } { 21 } \mathbf { k }\)
• D) \({\nabla} f = - \frac { 1 } { 21 } j \mathbf { j } - \frac { 1 } { 7 } k\)