The Total solution for NCERT class 6-12
Evaluate:
Since |AB|= |A||B|
= 2(17 × 12 – 5 × 20) – 3(13 × 12 – 5 × 15) + 7(13 × 20 – 15 ×17)
= 2 (204 – 100) – 3 (156 – 75) + 7 (260 – 255)
= 2×104 – 3×81 + 7×5
= 208 – 243 +35
= 0
Now |A|2 = |A|×|A|
|A|2= 0
