Math Is Fun Forum

soha

Real Member

Registered: 2006-07-07

Posts: 2,530

Matrices

IF

=

  then find the value of x & y

Last edited by soha (2010-03-20 17:20:27)

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"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!"
- David O. McKay

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Matrices

Hi soha;

x = 1
y = 0

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

soha

Real Member

Registered: 2006-07-07

Posts: 2,530

Re: Matrices

Hi,

Please tell the way by which you got this answer????

---

"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!"
- David O. McKay

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Matrices

Hi soha;

There is a quick trick using the rules of matrix multiplication but I will show you the extreme long way. That matrix equation represents a 2x2 simultaneous set of equations.

1x + 2y = 1
2x + 5y = 2

Do you see how I got that? Now solve.

x = 1 , y = 0.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

soha

Real Member

Registered: 2006-07-07

Posts: 2,530

Re: Matrices

Can you tell me the quick trick???? Please

---

"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!"
- David O. McKay

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Matrices

Hi soha;

The RHS is the same as the top row vector of the square matrix. So x = 1 and y = 0.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

soha

Real Member

Registered: 2006-07-07

Posts: 2,530

Re: Matrices

Top row vector????

this vector means
????

---

"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!"
- David O. McKay

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Matrices

The {1,2} in

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

soha

Real Member

Registered: 2006-07-07

Posts: 2,530

Re: Matrices

If the RHS is similar to that  1 and 2 ,,,

hw is x=1 and y=0?

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"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!"
- David O. McKay

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Matrices

Hi soha;

Did you understand post #4 that uses no tricks, but you must understand what that matrix equation represents.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

soha

Real Member

Registered: 2006-07-07

Posts: 2,530

Re: Matrices

I did'nt get how you got 1 and 0 there also?????????????

---

"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!"
- David O. McKay

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Matrices

Hi soha;

Do you know how to solve 2 equations simultaneously?

Your question in post one is just this:
1x + 2y = 1
2x + 5y = 2

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

soha

Real Member

Registered: 2006-07-07

Posts: 2,530

Re: Matrices

By adding or subtracting the equations?

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"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!"
- David O. McKay

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Matrices

Yes, that is one way, and the easiest.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

soha

Real Member

Registered: 2006-07-07

Posts: 2,530

Re: Matrices

Which One????

---

"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!"
- David O. McKay

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Matrices

Hi soha;

1)  1x + 2y = 1
2)  2x + 5y = 2

Times equation 1 by 2:

1)  2x + 4y = 2
2)  2x + 5y = 2

Subtract equation 1 from equation 2. You get:
y = 0

Plug that y = 0 back into equation 1.

x + 2(0) = 1
x = 1

So:

x = 1 and y = 0.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

soha

Real Member

Registered: 2006-07-07

Posts: 2,530

Re: Matrices

got it..

What is that trick .. RHS is similar to that 1 and 2 .. thn??

---

"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!"
- David O. McKay

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Matrices

Hi soha;

From the rules of matrix multiplication:

You see that the matrix on the RHS, in order for it to equal the top row vector of the LHS, x must be 1 and y must be 0.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

soha

Real Member

Registered: 2006-07-07

Posts: 2,530

Re: Matrices

ok..

understood it now !!!!

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"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!"
- David O. McKay