let u1 336 u2 444 and u3 633SolutionGiven that u1 336 u2
let u1 (3,3,6) u2 = (4,4,4) and u3 (-6,3,3)
Solution
Given that u1 = (3,3,6) , u2 = (4,4,4) and u3 =(-6,3,3)
v = (41,5,12)
Let v = c1 u1 + c2 u2 + c3u3 where c1,c2,c3 are constants.
Hence,
(41,5,12) = c1 (3,3,6)+ c2 (4,4,4) + c3 (-6,3,3)
(41,5,12) = (3c1 +4c2 -6c3, 3c1+4c2+3c3, 6c1+4c2+3c3)
Then,
3c1 +4c2 -6c3 = 41 --------- Eq (1)
3c1+4c2+3c3 = 5 ------------ Eq(2)
6c1+4c2+3c3 = 12 ----------- Eq (3)
Calucation of c3:
Eq (1) - Eq(2),gives c3 .
3c1 +4c2 -6c3 = 41 --------- Eq (1)
3c1+4c2+3c3 = 5 ------------ Eq(2)
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-9c3 = 36
c3 = -4
Calculation of c1:
Eq (2)- Eq(3) gives c1.
3c1+4c2+3c3 = 5 ------------ Eq(2)
6c1+4c2+3c3 = 12 ----------- Eq (3)
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-3c1 = -7
c1 = 7/3
Calculaton of c2:
Substitute values of c1 and c3 in Eq (1) to get c2.
3c1 +4c2 -6c3 = 41 --------- Eq (1)
3.(7/3) + 4c2 - 6(-4) = 41
7 + 4c2 +24 = 41
c2 = 10/4 = 5/2
Therefore,
c1 = 7/3, c2 = 5/2 , c3 =-4
Hence,
v = (7/3) u1 + (5/2) u2 -4 u3

