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JEE MATHEMATICS MCQ: DOT PRODUCT OF VECTORS

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If a⃗,b⃗,c⃗\mathbf{\vec a},\mathbf{\vec b},\mathbf{\vec c} are three non-zero, non-coplanar vectors and

b⃗1+b⃗−b⃗⋅a⃗∣a⃗∣2a⃗              ,b⃗2+b⃗−b⃗⋅a⃗∣a⃗∣2a⃗      {{\mathbf{\vec b}}_1} + \mathbf{\vec b} - \frac{{\mathbf{\vec b}\cdot\mathbf{\vec a}}}{{|\mathbf{\vec a}{|^2}}}\mathbf{\vec a}\;\;\;\;\;\;\;,{{\mathbf{\vec b}}_2} + \mathbf{\vec b} - \frac{{\mathbf{\vec b}\cdot\mathbf{\vec a}}}{{|\mathbf{\vec a}{|^2}}}\mathbf{\vec a}\;\;\;

And

  c⃗1+b⃗−c⃗⋅a⃗∣a⃗∣2a⃗+c⃗⋅b⃗∣b⃗∣2b⃗1  \mathrm{\;}{{\mathbf{\vec c}}_1} + \mathbf{\vec b} - \frac{{\mathbf{\vec c}\cdot\mathbf{\vec a}}}{{|\mathbf{\vec a}{|^2}}}\mathbf{\vec a} + \frac{{\mathbf{\vec c}\cdot\mathbf{\vec b}}}{{|\mathbf{\vec b}{|^2}}}{{\mathbf{\vec b}}_1}\;

c⃗2+c⃗−c⃗⋅a⃗∣a⃗∣2a⃗−c⃗⋅b⃗1∣b⃗1∣2b⃗1  ,      {{\mathbf{\vec c}}_2} + \mathbf{\vec c} - \frac{{\mathbf{\vec c}\cdot\mathbf{\vec a}}}{{|\mathbf{\vec a}{|^2}}}\mathbf{\vec a} - \frac{{\mathbf{\vec c}\cdot{{\mathbf{\vec b}}_1}}}{{|{{\mathbf{\vec b}}_1}{|^2}}}{{\mathbf{\vec b}}_1}\;,\;\;\;

c⃗3=c⃗−c⃗⋅a⃗∣c⃗∣2a⃗−c⃗⋅b⃗2∣c⃗∣2b⃗1,  {{\mathbf{\vec c}}_3} = \mathbf{\vec c} - \frac{{\mathbf{\vec c}\cdot\mathbf{\vec a}}}{{|\mathbf{\vec c}{|^2}}}\mathbf{\vec a} - \frac{{\mathbf{\vec c}\cdot{{\mathbf{\vec b}}_2}}}{{|\mathbf{\vec c}{|^2}}}{{\mathbf{\vec b}}_1},\;

c⃗4=c⃗−c⃗⋅a⃗∣c⃗∣2a⃗−b⃗⋅c⃗∣b⃗∣2b⃗1{{\mathbf{\vec c}}_4} = \mathbf{\vec c} - \frac{{\mathbf{\vec c}\cdot\mathbf{\vec a}}}{{|\mathbf{\vec c}{|^2}}}\mathbf{\vec a} - \frac{{\mathbf{\vec b}\cdot\mathbf{\vec c}}}{{|\mathbf{\vec b}{|^2}}}{{\mathbf{\vec b}}_1}

Then, which of the following is a set of mutually orthogonal vectors?
View answer and explanation
Correct option: B
{a⃗,  b⃗1,c⃗2}\left\{ {\mathbf{\vec a},\;{{\mathbf{\vec b}}_1},{{\mathbf{\vec c}}_2}} \right\}
Option B ({a⃗,  b⃗1,c⃗2}\left\{{\mathbf{\vec a},\;{{\mathbf{\vec b}}_1},{{\mathbf{\vec c}}_2}} \right\}) is correct because a⃗⋅b⃗1=0\mathbf{\vec a} \cdot \mathbf{\vec b}_1 = 0, a⃗⋅c⃗2=0\mathbf{\vec a} \cdot \mathbf{\vec c}_2 = 0, and b⃗1⋅c⃗2=0{\mathbf{\vec b}}_1 \cdot \mathbf{\vec c}_2 = 0, indicating mutual orthogonality.

More Questions from DOT PRODUCT OF VECTORS

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The distance between the planes given by r.(i+2j−2k)+5=0\mathbf{r} .(\mathbf{i}+2 \mathbf{j}-2 \mathbf{k})+5=0 and r−(i+2j−2k)−8=0\mathbf{r}-(\mathbf{i}+2 \mathbf{j}-2 \mathbf{k})-8=0 is A vector which makes equal angles with the vectors 13(i^−2j^+2k^),15(−4i^−3k^)\frac{1}{3}\left( {\hat i - 2\hat j + 2\hat k} \right),\frac{1}{5}\left( { - 4\hat i - 3\hat k} \right), and j^{\hat j}, is If vector a=2i^−3j^+6k^\mathbf{a}=2 \hat{\mathbf{i}}-3 \hat{\mathbf{j}}+6 \hat{\mathbf{k}} and vector b=−2i^+2j^−k^\mathbf{b}=-2 \hat{\mathbf{i}}+2 \hat{\mathbf{j}}-\hat{\mathbf{k}}, then  Projection of vector a on vector b Projection of vector b on vector a\frac{\text { Projection of vector } \mathbf{a} \text { on vector } \mathbf{b}}{\text { Projection of vector } \mathbf{b} \text { on vector } \mathbf{a}} is equal to The angle between a⃗{\mathbf{\vec a}} and b⃗{\mathbf{\vec b}} is 5π6\frac{{5\pi }}{6} and the projection of a⃗{\mathbf{\vec a}} in the direction of b⃗{\mathbf{\vec b}} is −63\frac{{ - 6}}{{\sqrt 3 }} then ∣a⃗∣\left| {\mathbf{\vec a}} \right| is equal to A velocity 14 m/s\frac{1}{4} \mathrm{~m} / \mathrm{s} is resolved into two components along OAO A and OBO B making angles 30∘30^{\circ} and 45∘45^{\circ} respectively with the given velocity. Then the component along OBO B is Find the equation of the perpendicular drown from the origin to the plane 2x+4y−5z=102x + 4y - 5z = 10
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