4. If \( \sin ( x y ) = x ^ { 2 } - y \) , find the derivative of \( y \) with respect to \( x \) . (find \( y ^ { \prime } ) \)
5. Find the derivative \( y ^ { \prime } \) if \( y = x \tan ( 2 x )\)
4. If \( \sin ( x y ) = x ^ { 2 } - y \) , find the derivative of \( y \) with respect to \( x \) . (find \( y ^ { \prime } ) \)
5. Find the derivative \( y ^ { \prime } \) if \( y = x \tan ( 2 x )\)