Understanding Engineering Mathematics

(やまだぃちぅ) #1
This chapter requires very little new material and much of it relies simply on Pythagoras’
theorem.

7.1 Review

7.1.1 Coordinate systems in a plane ➤205 220➤➤


A.Plot the points with Cartesian coordinates

(i) (0, 0) (ii) (0, 1) (iii) (−1, 3)

(iv) (−2, 4) (v) (− 2 ,− 3 ) (vi) (0,−1)

(vii) (3, 3) (viii) (3,−2)

B. Plot the points with polar coordinates (r, θ)

(i) (0, 0) (ii) (0,π) (iii) (1, 0) (iv)

(
1 ,

π
2

)

(v)

(
3 ,−

π
2

)
(vi)

(
2 ,

π
6

)
(vii)

(
6 ,

5 π
4

)
(viii)

(
5 ,

2 π
3

)

7.1.2 Distance between two points ➤208 221➤➤


Find the distance between the following pairs of points referred to rectangular Carte-
sian axes.

(i) (0, 0), (1, 1) (ii) (1, 2), (1, 3) (iii) (−2, 4), (1,−3)

(iv) (− 1 ,− 1 ),(− 2 ,− 3 )

7.1.3 Midpoint and gradient of a line ➤209 221➤➤


Find the (a) mid-point and (b) the gradient of the line segments joining the pairs of points
in Question 7.1.2.

7.1.4 Equation of a straight line ➤212 221➤➤


A.Determine the equations of the straight lines through the pairs of points in
Question 7.1.2.
B.Find the gradient and the intercepts on the axes of the lines


(i) y= 3 x+ 2 (ii) 2x+ 3 y= 1 (iii) y= 4 x

(iv) x+y+ 1 = 0
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