MCQ
A unit vector in the $xy - $ plane which is perpendicular to $4i - 3j + k$ is
- A$\frac{{i + j}}{{\sqrt 2 }}$
- ✓$\frac{1}{5}(3i + 4j)$
- C$\frac{1}{5}\,(3i - 4j)$
- DNone of these
Let vector be $xi + yj,$ then $4x - 3y = 0$
$ \Rightarrow 4x = 3y \Rightarrow x = \frac{3}{5},\,\,y = \frac{4}{5},$
Hence the required vector is $\frac{1}{5}(3i + 4j).$
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$x = 1 + xy\frac{{dy}}{{dx}} + \frac{{{{\left( {xy} \right)}^2}}}{{2!}}{\left( {\frac{{dy}}{{dx}}} \right)^2} + \frac{{{{\left( {xy} \right)}^3}}}{{3!}}{\left( {\frac{{dy}}{{dx}}} \right)^3} + ......$ is