Find the matrix T if ST = I where S = \(\begin{pmatrix} -1 & 1 \\ 1 & -2 \end{pmatrix}\)

a

\(\begin{pmatrix} -2 & -1 \\ -1 & -1 \end{pmatrix}\)

b

\(\begin{pmatrix} -2 & -1 \\ -1 & 1 \end{pmatrix}\)

c

\(\begin{pmatrix} -1 & -1 \\ 0 & -1 \end{pmatrix}\)

d

\(\begin{pmatrix} -1 & 1 \\ 0 & 1 \end{pmatrix}\)

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a

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Discussions (109)

Waldon95
13 years ago

Soln

[a^2(3/4)b^-3(3/4)c^(3/4)]divided by (a^-1b^4c^5)

===>(a^3/2b^-9/4c^3/4)divided by (a^-1b^4c^5).

Note a^p =3/2-(-1)==>p=5/2

q=-9/4-(4)===>q=-25/4

r=3/4-(5)===>r=-17/4

now p+2q

5/2+2(-25/4)

:- p+2q=-10.

Make use of indice...

lucybaby2008
13 years ago

Both d questn nd d answer is nt clear 2 me.

Madoxsky
13 years ago

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Waldon95
13 years ago

Soln


[a^2(3/4)b^-3(3/4)c^(3/4)]divided by (a^-1b^4c^5)


===>(a^3/2b^-9/4c^3/4)divided by (a^-1b^4c^5).


Note a^p =3/2-(-1)==>p=5/2


q=-9/4-(4)===>q=-25/4


r=3/4-(5)===>r=-17/4


now p+2q


5/2+2(-25/4)


:- p+2q=-10.


Make use of indice...

rachel b michael
13 years ago

dnt even undastand d qstion

sunday felicia
10 years ago

I SWEAR HEE NO EASY AT ALL.IS DIS D KIND OF QUESTION WE ARE GOIN TO FACE INSIDE HALL. BEFORE I FINISHE SOLVING DIS QUESTION INSIDE EXAM HALL,DERE WOULD BE ANYTIME LEFT.MAY GOD HELP US NI O

Felix Powell
12 years ago

Soln

{(a^2b^-3c)^3\4 /a^-1b^4c^5} =a^pb^qc^r

from the power law of indices.

(a^2b^-3c)^3\4 =a^2*3\4.b^-3*3\4.c^1*3\4

=a^3\2.b^-9\4.c^3\4

from the divisional law of indices

(a^3\a.b^-9\4.c^3\4)/a^-1.b^4.c^5 =

a^3\2+1.b^-9\4-4.c^3\4-5

=a^5\2.b-25\4.c^-17\4

Now by comparing the powers in a^p.b^q.c^r

p=5\2,b=-25\4,c=-17\4

substituting the values of p and q in the equation p+2q,we will have

5\2 + 2(-25\4) = 5\2- 25\2

=(5-25)\2 = -20\2 = -10 Ans.

Dagijoe
13 years ago

using the laws of indices u get the values of p=5/2, q=-25/4 and r=-17/4 then you solve p +2q which gives -10

Alwayz1999
9 years ago

Here is an explanation:

To solve this, it is simple though the question looks more complex.

Solution

(a^2 b^2 c)^3\4 divided by a^-1 b^4 c^5 equals to a^p b^q c^r.

First let's separate the question, let's put aside the equals to part, now



Multiply all the numerator through by the power of 3/4. You will get a^3/2 b^-9/4 c^3/4 after this, use law of indices to divide the numerator with the denominator so we have a^3/2 Γ· a^-1 b^-9/4 Γ· b^4 c^3/4 Γ· c^5 after using law of indices to solve it, you will get a^5/2 b^-25/4 c^-17/4. So after these we get our p,q,r by comparing the powers.

:. a^5/2 b^-25/4 c^-17/4 = a^p b^q c^r, so p = 5/2, q = -25/4 c = -17/4. So now P + 2Q = 5/2 + 2(-25/4) after solving this, you will get -10 which is the answer.

Thank you.

REF: Jamb, 1999

maxi957
13 years ago

This question is really great.what you need to first is to open the bracket then use indices to remove the division sign to subtraction sign then after which you compare to get p,q and r.then u can substitute it into p+2q.that's it.you just need to tink hard.

kingdomvic
13 years ago

a^6/4b^-9/4c^3/4 for d numerator wen u multiply 3/4 For d denominator q^-1b^4c^5

Apply the law of indices u will gt a^10/4b^-25/4c^-17/4(In a^p b^q c^r)

but the questn is d value of p+2q i.e p=10/4 q=-25/4 Substitute it in p+2q so 10/4+2(-25/4)=10/4-50/4 =40/4=-10

2009_melo
3 years ago

This question is somehow. The solution is simple but complicated.

ruthbaiby
10 years ago

the answer is c ; be it -25/4 or -13/2

Emmacodi
1 year ago

so the equation is
(a^2 b^-3 c)/a^-1 b^4c^5
and the questions is what is the value of p+2q
solu
p=2 q= -3
2q means 2 *q (-3)
so
p + 2q= 2+ 2* -3 = - 10
so the answer is - 10

VickyYong
3 years ago

everything is just confusing

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