Straight line in space — Maths STD 12 Science — Question
Gujarat BoardEnglish MediumSTD 12 ScienceMathsStraight line in space2 Marks
Question
Write the cartesian and vector equations of x-axis.
✓
Answer
Since x-axis passes through the point (0, 0, 0) having position vector $\vec{\text{a}}=0\hat{\text{i}}+0\hat{\text{j}}+0\hat{\text{k}}$ and is parallel to the vector $\vec{\text{b}}=1\hat{\text{i}}+0\hat{\text{j}}+0\hat{\text{k}}$ having direction ratios proportional to 1, 0, 0, the cartesian equation of x-axis is
$\frac{\text{x}-0}{1}=\frac{\text{y}-0}{0}=\frac{\text{z}-0}{0}$
$=\frac{\text{x}}{1}=\frac{\text{y}}{0}=\frac{\text{z}}{0}$
Also, its vector equation is
$\vec{\text{r}}=\vec{\text{a}}+\lambda\vec{\text{b}}$
$=0\hat{\text{i}}+0\hat{\text{j}}+0\hat{\text{k}}+\lambda\big(\hat{\text{i}}+0\hat{\text{j}}+0\hat{\text{k}}\big)$
$=\lambda\hat{\text{i}}$
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