Question

༒ Bʀᴀɪɴʟʏ Sᴛᴀʀs

༒Mᴏᴅᴇʀᴀᴛᴇʀs

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if a = 5i - j -3k and b= i+3j-5k, then show that the vectors a+b and a-b are perpendicular

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correct And best Answer i will drop 1000thanks​

Answer 1

Explanation:

a = 5i - j - 3k

b = i + 3j - 5k

a + b = ( 5+1 ) i + (-1+3 ) j + ( -3 -5 ) k

a + b = 6i + 2j - 8k

a - b = (5-1)i + (-1-3)j + (-3+5)k

a-b = 4i -4j+2k

so we need to show

(a+b).(a-b) = 0

(6i+2j-8k).(4i-4j+2k)

(6*4)+(2*-4)+(-8*2)

24-8-16

24-24

0

since (a+b).(a-b)=0

hence,(a+b) is perpendicular to (a-b)