engineering recuitment ISRO Scientific Assistant Physics 2020 Engineering Mathematics Calculus Vector Calculus
\(\vec r\) की दिशा में 1 / r का दिशात्मक अवकलज क्या है?
1
\(\frac {1}{r^2}\)
2
\(-\frac {1}{r^2}\)
3
\(\frac {1}{r^3}\)
4
\(-\frac {\vec r}{r^3}\)