Consider a △ABC, whose vertices are A(−8,2,4),B(4,−2,3) and C(1,3,2). Then the value of AB2−2BC2−AC2=
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Solution
Given : vertices of triangle A(−8,2,4),B(4,−2,3) and C(1,3,2) ⇒AB2=(4+8)2+(−2−2)2+(3−4)2⇒AB2=161, BC2=(4−1)2+(3+2)2+(2−3)2=35 and AC2=(1+8)2+(3−2)2+(2−4)2=86 ∴AB2−2BC2−AC2=161−2×35−86=5