# If |a|=11, |b|=23, |a-b|=30 then find |a+b| and angle between a and b

Arun
25750 Points
5 years ago
Dear student

(a- b).(a-b) = a² + b² - 2a.b
900 = 121 + 529 - 2* 11*23 cos @

cos @ = -125 /253

Hence @ = cos ^-1 ( -125/253)

Now

(a+b). (a+b) = a² + b² + 2a.b
|a+b|² = 121 + 529 -250 = 400

|a+b| = 20
Hi
15 Points
3 years ago

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