How to find the modulus of a vector?

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Can someone please explain to me how to do question 4 b iii) Thanks heaps!

2 Answers
Dec 22, 2017

|vec(OD)|=sqrt13

Explanation:

"given the vector "((x),(y))" then"

|((x),(y))|=sqrt(x^2+y^2)larrcolor(red)"magnitude of vector"

"here "vec(OD)=((3),(2))

rArr|vec(OD)|=sqrt(3^2+2^2)=sqrt13

Dec 22, 2017

|OD| = sqrt(13)

Explanation:

To understand this problem we must first know what modulus really means, in this case, the length of the vector...

So |OD| is just the length of the vector from O to D....

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We can see that we can form a right angle triangle, with sides 2 and 3 , so to find |OD| we can use pythagerous' theorem:

a^2 + b^2 = c^2

=> |OD|^2 = 3^2 + 2^2

=> |OD|^2 = 13

=> sqrt( |OD|^2 ) = sqrt(13)

=> |OD| = sqrt(13)