Chapter 28: Introduction to 3D coordinate geometry – Exercise 28.1

Introduction to 3D coordinate geometry – Exercise – 28.1 – Q.1(i)

Ans.

All are positive. So octant is XOYZ

Introduction to 3D coordinate geometry – Exercise – 28.1 – Q.1(ii)

Ans.

X is negative and rest are positive, so octant is X’OYZ

Introduction to 3D coordinate geometry – Exercise – 28.1 – Q.1(iii)

Ans.

Y is negative and rest are positive, so octant is XOY’Z 

Introduction to 3D coordinate geometry – Exercise – 28.1 – Q.1(iv)

Ans.

Z is negative and rest are positive, so octant is XOYZ’

Introduction to 3D coordinate geometry – Exercise – 28.1 – Q.1(v)

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X and Y are negative and Z is positive, so octant is X'OY'Z

Introduction to 3D coordinate geometry – Exercise – 28.1 – Q.1(vi)

Ans.

All are negative, so octant is X’OY’Z’

Introduction to 3D coordinate geometry – Exercise – 28.1 – Q.1(vii)

Ans.

Y and Z are negative, so octant is XOY’Z’

Introduction to 3D coordinate geometry – Exercise – 28.1 – Q.1(viii)

Ans.

X and Z are negative, so octant is X’OYZ’

Introduction to 3D coordinate geometry – Exercise – 28.1 – Q.2(i)

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YZ plane is x-axis, so sign of x will be changed. So answer is (2, 3, 4)

Introduction to 3D coordinate geometry – Exercise – 28.1 – Q.2(ii)

Ans.

XZ plane is y-axis, so sign of y will be changed. So answer is (-5, -4, -3)

Introduction to 3D coordinate geometry – Exercise – 28.1 – Q.2(iii)

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Introduction to 3D coordinate geometry – Exercise – 28.1 – Q.4

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