NCERT Solutions class-11 Maths Exercise 12.1

Exercise 12.1

1. A point is on the axis. What are its coordinates and coordinates?

Ans. We know that coordinates of any point on the axis will be Therefore, coordinate and coordinate of the point are zero.

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2. A point is on XZ-plane. What can you say about its coordinate?

Ans. We know that coordinates of any point in XZ-plane will be Therefore coordinate of the point is zero.

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3. Name the octants in which the following points lie:

Ans. Point (1, 2, 3) lies in I octant.

Point lines in IV octant.

Point lines in VIII octant.

Point lines in V octant.

Point lines in VIII octant.

Point lines in VIII octant.

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4. Fill in the blanks:

(i) The axis and axis taken together determine a plane known as ____________.

(ii) The coordinates of points in the XY-plane are of the form ____________.

(iii) Coordinates planes divide the space into ____________ octants.

Ans. (i) XY-plane

(ii)

(iii) Eight