Math Is Fun Forum

neela2

Guest

matrices

Hey everybody!

I've solved the a) and b) part of this question, I need help with part c).

Thanks

A matrix satisfies the equation PX = Y where

       (1  3
P =   2  6)

       (5
Y =   10)

a) show that when

X= (2
      1) the equation PX = Y is satisfied.

b) In the case when

x= (8
      k) the equation is also satisfied. Find the value of k.

c) Calculate
P = (3t
       -t) where t is any real number.

Hence or otherwise show that if
     2              (3
X=         +  t
     1               -1)

then the equation PX=Y is always satisfied.

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: matrices

I'm not sure what the first part of c) wants you to do.
P is a matrix and (3t is a vector, so they will never be equal.
                          -t)

The second part of it is easy enough though. Just calculate PX and you'll see that the t's all cancel and you get left with Y.

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Why did the vector cross the road?
It wanted to be normal.