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8.5.3 – Unit Vectors, Linear Combinations. In the case of vectors, we have a special vector known as the unit vector Unit Vector = any vector with a length 1; direction irrelevant Two special unit vectors we look at the most; i = {1, 0} j = {0, 1}. What would vector i represent?
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In the case of vectors, we have a special vector known as the unit vector • Unit Vector = any vector with a length 1; direction irrelevant • Two special unit vectors we look at the most; • i = {1, 0} • j = {0, 1}
What would vector i represent? • What would vector j represent?
Regardless of the vector, any vector may be written in terms of the vector i and j • {a, b} = a{1,0} + b{0, 1} = ai + bj • Known as a Linear Combination • LC = sum of scalar multiples of vectors
Finding LC • To find linear combinations of vectors in terms of a select unit vector, and vector i and j; • The scalar awill be represented by; • a = 1/|| u || • This will give us the unit vector in the same direction as a given vector u
To write the linear combination, just take out the horizontal/vertical component of the component form • Example. If u = {-5, 3}, then u = -5i + 3j
Example. Let u = {6. -3}. Find a unit vector pointing in the same direction as u. • Example. Write the given vector as a linear combination of iand j.
Example. Let u = {-4, -8}. Find a unit vector pointing in the same direction as u. • Example. Write the given vector as a linear combination of iand j.
Example. Let u = {2, 3}. Find a unit vector pointing in the same direction as u. • Example. Write the given vector as a linear combination of iand j.
Assignment • Pg. 667 • 27-32