Get Answers to all your Questions

header-bg qa

Need Solution for R.D.Sharma Maths Class 12 Chapter 22 Algebra of Vectors  Exercise very Short Answer type Question 49 Maths Textbook Solution.

Answers (1)

Answer: 6\hat{i}-9\hat{j}+18\hat{k}

Hint: You must know the rules of vector functions

Given: Find vector in direction of 2\hat{i}-3\hat{j}+6\hat{k}having magnitude 21 units

Solution: Let \vec{a}=2\hat{i}-3\hat{j}+6\hat{k}

      Unit vector

\begin{aligned} &\frac{\vec{a}}{|\vec{a}|}=\frac{(2 \hat{i}-3 \hat{j}+6 \hat{k})}{\sqrt{2^{2}+(-3)^{2}+(6)^{2}}}\\ \end{aligned}

\begin{aligned} &=\frac{(2 \hat{i}-3 \hat{j}+6 \hat{k})}{\sqrt{49}}\\ \end{aligned}

\begin{aligned} &=\frac{(2 \hat{i}-3 \hat{j}+6 \hat{k})}{7}\\ \end{aligned}

We know, magnitude is 21 units

\begin{aligned} &|\vec{a}|=21\\ \end{aligned}

\begin{aligned} &\frac{\vec{a}}{21}=\frac{1}{7}(2 \hat{i}-3 \hat{j}+6 \hat{k})\\ \end{aligned}

\begin{aligned} &\vec{a}=3(2 \hat{i}-3 \hat{j}+6 \hat{k})\\ \end{aligned}

\begin{aligned} &=6 \hat{i}-9 \hat{j}+18 \hat{k} \end{aligned}

Posted by

infoexpert21

View full answer

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads