590 likes | 1k Views
Vectors. Chapter 46. A VECTOR?. Describes the motion of an object A Vector comprises Direction Magnitude We will consider Column Vectors General Vectors Vector Geometry. Size. NOTE! Label is in BOLD . When handwritten, draw a wavy line under the label i.e. a. Column Vectors.
E N D
Vectors Chapter 46 ch46 Vectors by Chtan FYKulai
A VECTOR? • Describes the motion of an object • A Vector comprises • Direction • Magnitude • We will consider • Column Vectors • General Vectors • Vector Geometry Size ch46 Vectors by Chtan FYKulai
NOTE! Label is in BOLD. When handwritten, draw a wavy line under the label i.e. a Column Vectors Vector a 2 up 4 RIGHT COLUMN Vector ch46 Vectors by Chtan FYKulai
b Column Vectors Vector b 2 up 3 LEFT COLUMN Vector? ch46 Vectors by Chtan FYKulai
n Column Vectors Vector u 2 down 4 LEFT COLUMN Vector? ch46 Vectors by Chtan FYKulai
b a d c Describe these vectors ch46 Vectors by Chtan FYKulai
Alternative labelling F B D E G C A H ch46 Vectors by Chtan FYKulai
k k k k General Vectors A Vector has BOTH a Length & a Direction All 4 Vectors here are EQUAL in Length and Travel in SAME Direction. All called k k can be in any position ch46 Vectors by Chtan FYKulai
k General Vectors Line CD is Parallel to AB B CD is TWICE length of AB D A 2k Line EF is Parallel to AB E EF is equal in length to AB C -k EF is opposite direction to AB F ch46 Vectors by Chtan FYKulai
k Write these Vectors in terms of k B D 2k F G ½k 1½k E C -2k A H ch46 Vectors by Chtan FYKulai
B k D A C Combining Column Vectors ch46 Vectors by Chtan FYKulai
C B A Simple combinations ch46 Vectors by Chtan FYKulai
Q P R a b O Vector Geometry Consider this parallelogram Opposite sides are Parallel OQ is known as the resultant of a and b ch46 Vectors by Chtan FYKulai
Resultant of Two Vectors • Is the same, no matter which route is followed • Use this to find vectors in geometrical figures ch46 Vectors by Chtan FYKulai
. S is the Midpoint of PQ. Work out the vector Q S P R a b O e.g.1 = a + ½b ch46 Vectors by Chtan FYKulai
. Q S S is the Midpoint of PQ. Work out the vector P R a b O Alternatively - ½b = b + a = ½b + a = a + ½b ch46 Vectors by Chtan FYKulai
C p M Find BC = + A q B BC BA AC AC= p, AB = q e.g.2 M is the Midpoint of BC = -q + p = p - q ch46 Vectors by Chtan FYKulai
C p M Find BM = ½BC A q B BM AC= p, AB = q e.g.3 M is the Midpoint of BC = ½(p – q) ch46 Vectors by Chtan FYKulai
C p M Find AM + ½BC = A q B AB AM AC= p, AB = q e.g.4 M is the Midpoint of BC = q + ½(p – q) = q +½p - ½q = ½q +½p = ½(q + p) = ½(p + q) ch46 Vectors by Chtan FYKulai
C p M Find AM + ½CB = A q B AM AC AC= p, AB = q Alternatively M is the Midpoint of BC = p + ½(q – p) = p +½q - ½p = ½p +½q = ½(p + q) ch46 Vectors by Chtan FYKulai
Distribution’s law : The scalar multiplication of a vector : ch46 Vectors by Chtan FYKulai
Other important facts : ch46 Vectors by Chtan FYKulai
A vector with the starting point from the origin point is called position vector. 位置向量 ch46 Vectors by Chtan FYKulai
Every vector can be expressed in terms of position vector. ch46 Vectors by Chtan FYKulai
e.g.5 Given that , and also Find the values of ch46 Vectors by Chtan FYKulai
e.g.6 Given that ,, and are parallel. Find the value of ch46 Vectors by Chtan FYKulai
e.g.7 =, , a point . Find the coordinates of then express point in terms of . ch46 Vectors by Chtan FYKulai
e.g.8 If , , find the coordinates of ch46 Vectors by Chtan FYKulai
e.g.9 Given that ,, and are parallel. Find the value of ch46 Vectors by Chtan FYKulai
Magnitude of a vector ch46 Vectors by Chtan FYKulai
Unit vector : ch46 Vectors by Chtan FYKulai
e.g.10 Find the magnitude of the vectors : (b) ch46 Vectors by Chtan FYKulai
e.g.11 Find the unit vectors in e.g. 10 : (b) ch46 Vectors by Chtan FYKulai
Ratio theorem A P B ch46 Vectors by Chtan FYKulai
e.g.12 M is the midpoint of AB, find in terms of . ch46 Vectors by Chtan FYKulai
e.g.13 3 P divides AB into 2:3. Find in terms of . 2 ch46 Vectors by Chtan FYKulai
Application of vector in plane geometry e.g.14 In the diagram, CB=4CN, NA=5NX, M is the midpoint of AB. A M X B C N (a) Express the following vectors in terms of u and v ; (i) (ii) ch46 Vectors by Chtan FYKulai
(b) Show that (c) Calculate the value of (i) (ii) ch46 Vectors by Chtan FYKulai
Soln: (a) (i) (ii) (b) ch46 Vectors by Chtan FYKulai
(c) (i) (ii) ch46 Vectors by Chtan FYKulai
e.g.15 A M and N are midpoints of AB, AC. Prove that N M C B ch46 Vectors by Chtan FYKulai
e.g.16 B In the diagram K divides AD into 1:l, and divides BC into 1:k . 2a 1 A 1 K 6a l k D O C 2b 6b Express position vector OK in 2 formats. Find the values of k and l. ch46 Vectors by Chtan FYKulai
More exercises on this topic : 高级数学高二下册 Pg 33 Ex10g ch46 Vectors by Chtan FYKulai
Scalar product of two vectors If a and b are two non-zero vectors, θ is the angle between the vectors. Then , ch46 Vectors by Chtan FYKulai
Scalar product of vectors satisfying : Commutative law : Associative law : Distributive law : ch46 Vectors by Chtan FYKulai
e.g.17 Find the scalar product of the following 2 vectors : ch46 Vectors by Chtan FYKulai
e.g.18 If , find the angle between them. If are perpendicular, find k. ch46 Vectors by Chtan FYKulai
Scalar product (special cases) 1. Two perpendicular vectors Unit vector for y-axis N.B. Unit vector for x-axis ch46 Vectors by Chtan FYKulai
2. Two parallel vectors N.B. ch46 Vectors by Chtan FYKulai
e.g.19 Given , Find . Ans:[17/2] ch46 Vectors by Chtan FYKulai