Question

|A| - 11,|BI - 23 and |A-B|=30, find the value of |A+B|.​

Answer 1

Answer:

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