1.As the set { v1,v2,v3 } span a subspace of R4
then, c1v1+c2v2+c3v3=0
c1(1,1,−5,−6)+c2(2,0,2,−2)+c3(3,−1,0,8)=0
We get following equations from above equation
c1+2c2+3c3=0
c1−c3=0
−5c1+2c2=0
−6c1−2c2+8c3=0
From the above equation we can easily conclude that c1=c2=c3=0
So,{ v1,v2,v3 } are linearly independent.
Thus, the set is the basis for the subspace of R4.
2.As the set v1,v2,v3,v4 span R4.
then,c1v1+c2v2+c3v3+c4v4=0
c1(1,0,1,1)+c2(−4,4,−1,4)+c3(2,4,5,10)+c4(−10,4,−7,−2)=0
We get equations:
c1−4c2+2c3−10c4=0
4c2+4c3+4c4=0
c1−c2+5c3−7c4=0
c1+4c2+10c3−2c4=0
Solving these equations we can easily get
c1=−6c3+6c4
c2=−c3−c4
c3=arbitrary
c4=arbitrary
{ v1,v2 } span { v3,v4 }
{v1,v2 } spans a subspace of R4 and vectors are linearly independent.Thus,vectors serve as the basis of a subspace of R4.
3.c1v1+c2v2+c3v3+c4v4+c5v5=0
c1(1,−1,5,2)+c2(−2,3,1,0)+c3(5,−6,14,6)+c4(0,4,2,−3)+c5(3,15,45,2)=0
We get the following equations from the above equation.
c1−2c2+5c3+3c5=0
−c1+3c2−6c3+4c4+15c5=0
5c1+c2+14c3+2c4+45c5=0
2c1+6c3−3c4+2c5=0
Solving these equations we can get:
c1=−3c3−7c5
c2=c3−2c5
c3=arbitrary
c4=−4c5
c5=arbitrary
{v1,v2,v4 } span {v3,v5 }
{ v1,v2,v4 } span a subspace of R4 and vectors are linearly independent.Thus, vectors serve as the basis of a subspace of R4.
4.A=[364−9]
B=[−115]
B=c1(36)+c2(4−9)
3c1+4c2=−1
6c1−9c2=15
c1=1,c2=−1
Yes, B is in the column space of A as it can be expressed as a linear combination of column vectors of A.
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