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Provide solution for RD Sharma maths class 12 chapter 28 The Plane exercise multiple choice question 14

Answers (1)

Answer:

 Option (c)

Hint:

 Calculate the perpendicular distance of the plane from the origin.

Given:

 \frac{x-1}{3}=\frac{y-1}{0}=\frac{z-1}{4}

Solution:

Let, the equation of the plane be Ax + By + Cz + D = 0, as the plane is perpendicular to, so

We have,

A = 3, B = 0  and C = 4 as the plane passes through (1, 1, 1), we have,

\begin{aligned} &(A\times 1)+(B\times 1)+(C\times 1)+D=0\\ &A+B+C+D=0\\ &3+0+4+D=0\\ &D=-7 \end{aligned}

So, the equation of the plane becomes

3x + 4z - 7 = 0

Now, the perpendicular distance of the plane from the origin is

\begin{aligned} &\frac{\left | Ax_0+By_0+Cz_0+D \right |}{\sqrt{A^2+B^2+C^2}}=\frac{\left | (3\times 0)+(0\times 0)+(4\times 0)-7 \right |}{\sqrt{3^2+0^2+4^2}}\\ &\left [ \because (x_0, y_0,z_0)\approx (0,0,0) \right ]\\ &=\frac{\left | 0-7 \right |}{\sqrt{9+16}}\\ &=\frac{\left | -7 \right |}{\sqrt{25}}\\ &=\frac{7}{5} \end{aligned}

Posted by

Gurleen Kaur

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