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If the vectors phati+hatj+hatk, hati, qhatj+hatk and hati+hatj+rhatk(p ne q ne r ne1) are coplanar, then the value of pqr-(p+q+r) is |
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Answer» `-2` Since, a, b and c are coplanar . `:. [a,b,c]= 0 rArr |{:(p,1,1),(1,q,1),(1,1,r):}| = 0` `rArr p(qr- 1) - 1 (r-1) + 1 (1-q) = 0` `rArr PQR - p -r + 1 + 1-q = 0` `:. pqr - (p+q+r) = - 2` |
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