Q. Check that the four points P(2,4,4), Q(3,1,6), R(2,8,0), and S(5,2,3) all lie in a plane
Calculate Vectors: Find the vectors PQ, PR, and PS using the coordinates of the points.PQ=Q−P=(3−2,1−4,6−4)=(1,−3,2)PR=R−P=(2−2,8−4,0−4)=(0,4,−4)PS=S−P=(5−2,2−4,3−4)=(3,−2,−1)
Check Coplanarity: Check if the vectors PQ, PR, and PS are coplanar by finding the scalar triple product.The scalar triple product of vectors a, b, and c is given by [abc]=a⋅(b×c).First, calculate the cross product of PR and PS.PR \times PS = \left| \begin{array}{ccc}\(\newlinei & j & k (\newline\)0 & 4 & -4 (\newline\)3 & -2 & -1 (\newline\)\end{array} \right|\)=(4⋅−1−(−4)⋅−2)i−(0⋅−1−(−4)⋅3)j+(0⋅−2−4⋅3)k=(−4−8)i−(0+12)j+(0−12)k=(−12)i−(12)j−(12)k=(−12,−12,−12)
Calculate Dot Product: Now, calculate the dot product of PQ and the cross product of PR and PS.PQ⋅(PR×PS)=(1,−3,2)⋅(−12,−12,−12)= 1∗(−12)+(−3)∗(−12)+2∗(−12)= −12+36−24= 0
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