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paper 2 2005 - HSN forum

# paper 2 2005

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### #1laura_lou92

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Posted 20 May 2009 - 03:53 PM

Can anyone remind me how to find the angle between two lines in the vectors topic please? =S

### #2SncZ

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Posted 20 May 2009 - 04:17 PM

theta = inverse cos( (a.b)/(|a||b|) )

where |a| and |b| are the lengths of a and b respectively

a.b is the dot product = a1b1 + a2b2 + a3b3 +.......+ anbn where a1 represents the first component of vecor a. b1 represented similiar.

.... and theta is the angle between the two lines

### #3laura_lou92

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Posted 20 May 2009 - 04:21 PM

QUOTE (SncZ @ May 20 2009, 05:17 PM) <{POST_SNAPBACK}>
theta = inverse cos( (a.b)/(|a||b|) )

where |a| and |b| are the lengths of a and b respectively

a.b is the dot product = a1b1 + a2b2 + a3b3 +.......+ anbn where a1 represents the first component of vecor a. b1 represented similiar.

.... and theta is the angle between the two lines

Thanks.. mind is just going blanck. not a gd thing a day before the exam

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