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Provide Solution For R.D.Sharma Maths Class 12 Chapter 23 Scalar or Dot Products  Exercise 23.1 Question 10 Maths Textbook Solution.

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Answer: proved

Hint: you must know the rules of proving vector

Given: if \vec{a},\vec{b},\vec{c} are these mutually perpendicular unit vectors, prove that \mid \vec{a}+\vec{b}+\vec{c}\mid =\sqrt{3}

Solution: given that \vec{a},\vec{b}and \vec{c} are unit vectors

So, \mid \vec{a}\mid =1,\mid \vec{b}\mid =1,\mid \vec{c}\mid =1

Since they are mutually perpendicular

\begin{aligned} &\vec{a} \cdot \vec{b}=\vec{b} \cdot \vec{c}=\vec{c} \cdot \vec{a}=0 \\ \end{aligned}

Now,\begin{aligned} &|\vec{a}+\vec{b}+\vec{c}|^{2}=|\hat{a}|^{2}+|\hat{b}|^{2}+|\hat{c}|^{2}+2 \hat{a} \cdot \hat{b}+2 \hat{b} \cdot \hat{c}+2 \hat{c} \cdot \hat{a} \\ \end{aligned}

\begin{aligned} &=1+1+1+0+0+0 \\\\ &|\vec{a}+\vec{b}+\vec{c}|^{2} \Rightarrow 3 \\\\ &|\vec{a}+\vec{b}+\vec{c}| \Rightarrow \sqrt{3} \end{aligned}

=Proved

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