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Provide solution for RD Sharma maths class 12 chapter 27 Straight Line in Space exercise 27.1 question 18 maths textbook solution

Answers (1)

Answer :-

(\hat{\imath}+2 \hat{\jmath}-\hat{k})+\lambda(7 \hat{\imath}-5 \hat{\jmath}+\hat{k})

Hint :-

\overrightarrow{r}=\overrightarrow{a}+\lambda \overrightarrow{b}

Given :-

A(1,2,-1) \& 5 x-25=14-7 y=35 z

Solution :-

5 x-25=14-7 y=35 z \\ \Rightarrow \frac{x-5}{\frac{1}{5}}=\frac{y-2}{\frac{-1}{7}}=\frac{z}{\frac{1}{35}} \\ \Rightarrow \frac{x-5}{7}=\frac{y-2}{-5}=\frac{z}{1}  --------------  (1)

Direction ratios of (1)  will be ( 7 , -5 , 1 )

hence, \vec{b}=7 \hat{\imath}-5 \hat{\jmath}+\hat{k}

P.V of  A(1,2,-1)=>\vec{a}=\hat{\imath}+2 \hat{\jmath}-\hat{k} \\

\vec{r}=\vec{a}+\lambda \vec{b} \\ \quad

    =(\hat{\imath}+2 \hat{\jmath}-\hat{k})+\lambda(7 \hat{\imath}-5 \hat{\jmath}+\hat{k})

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