User:Pingusam

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EQUATION

3x +  2y - 3z = -5\,
4x + 3y - 4z = -8\,
-5x -  4y +  4z = 9\,
B = \begin{bmatrix} 3 & 2 & -3 &   | & 1 & 0 & 0  \\ 4 & 3 & -4 &   | & 0 & 1 & 0  \\ -5 & -4 & 4 & | &  0 & 0 & 1 \end{bmatrix}
B = \begin{bmatrix} -3 & -4 & 0 &   | & 4 & 0 & 3  \\ 4 & 3 & -4 &   | & 0 & 1 & 0  \\ -5 & -4 & 4 & | &  0 & 0 & 1 \end{bmatrix}
B = \begin{bmatrix} -3 & -4 & 0 &   | & 4 & 0 & 3  \\ -1 & -1 & 0 &   | & 0 & 1 & 1  \\ -5 & -4 & 4 & | &  0 & 0 & 1 \end{bmatrix}
B = \begin{bmatrix} -3 & -4 & 0 &   | & 4 & 0 & 3  \\ 0 & 1 & 0 &   | & -4 & 3 & 0  \\ -5 & -4 & 4 & | &  0 & 0 & 1 \end{bmatrix}
B = \begin{bmatrix} -3 & -4 & 0 &   | & 4 & 0 & 3  \\ 0 & 1 & 0 &   | & -4 & 3 & 0  \\ 0 & -8 & -12 & | &  20 & 0 & 12 \end{bmatrix}
B = \begin{bmatrix} -3 & -4 & 0 &   | & 4 & 0 & 3  \\ 0 & 1 & 0 &   | & -4 & 3 & 0  \\ 0 & 0 & -12 & | &  -12 & 24 & 12 \end{bmatrix}
B = \begin{bmatrix} -3 & 0 & 0 &   | & -12 & 12 & 3  \\ 0 & 1 & 0 &   | & -4 & 3 & 0  \\ 0 & 0 & -12 & | &  -12 & 24 & 12 \end{bmatrix}
B = \begin{bmatrix} 1 & 0 & 0 &   | & 4 & -4 & -1  \\ 0 & 1 & 0 &   | & -4 & 3 & 0  \\ 0 & 0 & 1 & | &  1 & -2 & -1 \end{bmatrix}
B^{-1} = \begin{bmatrix} 4 & -4 & -1  \\ -4 & 3 & 0  \\ 1 & -2 & -1 \end{bmatrix}
\begin{bmatrix} x \\ y \\ z\end{bmatrix} = \begin{bmatrix} 4 & -4 & -1  \\ -4 & 3 & 0  \\ 1 & -2 & -1 \end{bmatrix} \begin{bmatrix} -5 \\ -8  \\ 9  \end{bmatrix} = \begin{bmatrix} 3 \\ -4 \\ 2\end{bmatrix}
x = 3\,
y=-4\,
z=2\,


ECHELON

6x +  y + 2z = 5\,
8x + 3y + 4z = 5\,
2x -  y -  z = 6\,
A = \begin{bmatrix} 6 & 1 & 2 &   | & 5  \\ 8 & 3 & 4 &   | &  5 \\ 2 & -1 & -1 & | &  6 \end{bmatrix}
A = \begin{bmatrix} 8 & 0 & 1 &   | & 11  \\ 8 & 3 & 4 &   | &  5 \\ 2 & -1 & -1 & | &  6 \end{bmatrix}
A = \begin{bmatrix} 8 & 0 & 1 &   | & 11  \\ 8 & 3 & 4 &   | &  5 \\ 14 & 0 & 1 & | &  23 \end{bmatrix}
A = \begin{bmatrix} 8 & 0 & 1 &   | & 11  \\ 0 & 3 & 3 &   | &  -6 \\ 14 & 0 & 1 & | &  23 \end{bmatrix}
A = \begin{bmatrix} -6 & 0 & 0 &   | & -12  \\ 0 & 3 & 3 &   | &  -6 \\ 14 & 0 & 1 & | &  23 \end{bmatrix}
A = \begin{bmatrix} 1 & 0 & 0 &   | & 2  \\ 0 & 3 & 3 &   | &  -6 \\ 14 & 0 & 1 & | &  23 \end{bmatrix}
x +  0y + 0z = 2\,
0x + 3y + 3z = -6\,
14x +  0y   z = 23\,
x = 2\, as [1]\,
3y + 3z = -6\, as [2]\,
14x + z = 23\, as [3]\,

Substituting [1]\, in to [3]\,

14(2) + z = 23\,
28 + z = 23\,
z = -5\, as [4]\,

Substituting [4]\, in to [2]\,

3y + 3(-5) = -6\,
3y -15 = -6\,
3y = 9\,
y  = 3\,

MAGIC SQUARE

a +  g = 13\,
c +  e = 13\,
b +  f = 26\,
d +  h = 24\,
a +  b = 11\,
c +  d = 15\,
e +  f = 25\,
g +  h = 25\,
e +  g = 21\,
a +  c + f+h = 34\,
M=  \begin{bmatrix}     1 & 0 & 1 & 0 & 0 & 1 & 0 & 1\\     1 & 1 & 0 & 0 & 0 & 0 & 0 & 0\\     0 & 0 & 1 & 1 & 0 & 0 & 0 & 0\\     0 & 0 & 0 & 0 & 1 & 1 & 0 & 0\\     0 & 0 & 0 & 0 & 0 & 0 & 1 & 1\\     0 & 1 & 0 & 0 & 0 & 1 & 0 & 0\\     0 & 0 & 0 & 1 & 0 & 0 & 0 & 1\\     0 & 0 & 1 & 0 & 1 & 0 & 0 & 0\\   \end{bmatrix}
A= \begin{bmatrix} 34\\ 11\\ 15\\ 25\\ 25\\ 26\\ 24\\ 13 \end{bmatrix}
\begin{bmatrix}     1 & 0 & 1 & 0 & 0 & 1 & 0 & 1\\     1 & 1 & 0 & 0 & 0 & 0 & 0 & 0\\     0 & 0 & 1 & 1 & 0 & 0 & 0 & 0\\     0 & 0 & 0 & 0 & 1 & 1 & 0 & 0\\     0 & 0 & 0 & 0 & 0 & 0 & 1 & 1\\     0 & 1 & 0 & 0 & 0 & 1 & 0 & 0\\     0 & 0 & 0 & 1 & 0 & 0 & 0 & 1\\     0 & 0 & 1 & 0 & 1 & 0 & 0 & 0\\   \end{bmatrix} \begin{bmatrix} 34\\ 11\\ 15\\ 25\\ 25\\ 26\\ 24\\ 13 \end{bmatrix} = \begin{bmatrix} a\\ b\\ c\\ d\\ e\\ f\\ g\\ h \end{bmatrix}
\begin{bmatrix} a\\ b\\ c\\ d\\ e\\ f\\ g\\ h \end{bmatrix} = \begin{bmatrix} 1\\ 10\\ 4\\ 11\\ 9\\ 16\\ 12\\ 13 \end{bmatrix}


MATHS B QUESTION 1 A

y = 2(x-4)^3 - 7\,
y = 2((x-4)(x-4)(x-4)) - 7\,
y = 2((x^2-8x+16)(x-4)) - 7\,
y = 2(x^3 - 4x^2 - 8x^2 + 32x + 16x -64)-7\,
y = 2x^3 - 8x^2 - 16x^2 + 64x + 32x - 128 - 7\,
y = 2x^3 -24x^2 + 96x -135\,
a = 2\,
b = -24\,
c = 96\,
d = -135\,

MATHS C LAST QUESTION

A = \begin{bmatrix} 360\div1400 & 40\div1700 & 400\div2000  \\ 240\div1400 & 160\div1700 & 520\div2000  \\ 50\div1400 & 650\div1700 & 430\div2000  \end{bmatrix}
= \begin{bmatrix} 9\div35 & 40\div85 & 1\div5  \\ 6\div35 & 8\div85 & 13\div50  \\ 1\div28 & 1\div34 & 43\div200  \end{bmatrix}
D= \begin{bmatrix} 800  \\ 900  \\ 1000 \end{bmatrix}
P.Inp.= \begin{bmatrix} 750  \\ 850  \\ 650 \end{bmatrix}
Labour= \begin{bmatrix} 750\times  .8\\ 850\times.6  \\ 650\times.7 \end{bmatrix}
= \begin{bmatrix} 600\\ 510  \\ 455 \end{bmatrix}

X = (I_3 - A)^{-1} D\,

X = \begin{bmatrix} 1766.40\\ 1995.42  \\ 2326.17 \end{bmatrix}
New Labour = \begin{bmatrix} 1766.40\times(3\div7)\\ 1995.42\times.3  \\ 2326.17\times.2275 \end{bmatrix}
= \begin{bmatrix} 756.86\\ 598.63  \\ 529.20 \end{bmatrix}

EQUATION

-2x -  2y + 3z = -5\,
6x + 5y - 8z = -8\,
-3x -  y +  3z = 9\,
Q = \begin{bmatrix} -2 & -2 & 3 \\ 6 & 5 & -8 \\ -3 & -1 & 3 \end{bmatrix}
{det}Q =  ( -2 \times {det}\begin{bmatrix} 5 & -8\\ -1 & 3 \\ \end{bmatrix})  -  ( -2 \times {det}\begin{bmatrix} 6 & -8\\ -3 & 3 \\ \end{bmatrix})  +  ( 3 \times {det}\begin{bmatrix} 6 & 5\\ -3 & -1 \\ \end{bmatrix})
{det}Q = (-2 \times ((5 \times 3) - (-8 \times -1)))  -  (-2 \times ((6 \times 3) - (-8 \times -3)))  +  (3 \times ((6 \times -1) - (5 \times -3)))
{det}Q = (-2 \times 7) - (-2 \times -6) + (3 \times 9)
{det}Q = 1\,

↔↔↔↔↔↔↔↔↔↔↔↔

Q_x = \begin{bmatrix} -3 & -2 & 3 \\ 5 & 5 & -8 \\ 5 & -1 & 3 \end{bmatrix}

{det}Q_x =  ( -3 \times {det}\begin{bmatrix} 5 & -8\\ -1 & 3 \\ \end{bmatrix})  -  ( -2 \times {det}\begin{bmatrix} 5 & -8\\ 5 & 3 \\ \end{bmatrix})  +  ( 3 \times {det}\begin{bmatrix} 5 & 5\\ 5 & -1 \\ \end{bmatrix})

{det}Q_x = (-2 \times ((5 \times 3) - (-8 \times -1)))  -  (-2 \times ((5 \times 3) - (-8 \times 5)))  +  (3 \times ((5 \times -1) - (5 \times 5)))

{det}Q_x = (-3 \times 7) - (-2 \times 55) + (3 \times -30)
{det}Q = -1\,

↔↔↔↔↔↔↔↔↔↔↔↔

Q_y = \begin{bmatrix} -2 & -3 & 3 \\ 6  & 5 & -8 \\ -3 & 5 & 3 \end{bmatrix}

{det}Q_y =  ( -3 \times {det}\begin{bmatrix} 5 & -8\\ -1 & 3 \\ \end{bmatrix})  -  ( -3 \times {det}\begin{bmatrix} 6 & -8\\ -3 & 3 \\ \end{bmatrix})  +  ( 3 \times {det}\begin{bmatrix} 6 & 5\\ -3 & 5 \\ \end{bmatrix})

{det}Q_y = (-2 \times ((5 \times 3) - (-8 \times 5)))  -  (-3 \times ((6 \times 3) - (-8 \times -3)))  +  (3 \times ((6 \times 5) - (5 \times -3)))

{det}Q_y = (-2 \times 55) - (-3 \times -6) + (3 \times 45)
{det}Q_y = 7\,

↔↔↔↔↔↔↔↔↔↔↔↔

Q_z = \begin{bmatrix} -2 & -2 & -3 \\ 6  & 5 & 5 \\ -3 & -1 & 5 \end{bmatrix}

{det}Q_z =  ( -2 \times {det}\begin{bmatrix} 5 & 5\\ -1 & 5 \\ \end{bmatrix})  -  ( -2 \times {det}\begin{bmatrix} 6 & 5\\ -3 & 5 \\ \end{bmatrix})  +  ( -3 \times {det}\begin{bmatrix} 6 & 5\\ -3 & -1 \\ \end{bmatrix})

{det}Q_z = (-2 \times ((5 \times 5) - (-1 \times 5)))  -  (-2 \times ((6 \times 5) - (5 \times -3)))  +  (-3 \times ((6 \times -1) - (5 \times -3)))

{det}Q_z = (-2 \times 30) - (-2 \times 45) + (-3 \times 7)
{det}Q_z = 3\,

C = \begin{bmatrix} 1 & 1 & 2  \\ 2 & 2 & 3 \\ 2 & 3 & 3 \end{bmatrix}
C^t = \begin{bmatrix} 1 & 2 & 2  \\ 1 & 2 & 3 \\ 2 & 3 & 3 \end{bmatrix}
C^t = \begin{bmatrix} 1 & 2 & 2 & | & 140  \\ 1 & 2 & 3 & | & 150  \\ 2 & 3 & 3 & | & 210 \end{bmatrix}
C^t = \begin{bmatrix} 1 & 2 & 0 & | & 120  \\ 1 & 2 & 3 & | & 150  \\ 2 & 3 & 3 & | & 210 \end{bmatrix}
C^t = \begin{bmatrix} 1 & 2 & 0 & | & 120  \\ -1 & -1 & 0 & | & -60  \\ 2 & 3 & 3 & | & 210 \end{bmatrix}
C^t = \begin{bmatrix} -1 & 0 & 0 & | & 0  \\ -1 & -1 & 0 & | & -60  \\ 2 & 3 & 3 & | & 210 \end{bmatrix}
-a +  0f + 0q = 0\,
-a - f + 0q = -60\,
2a +  2f +  3q = 210\,
a = 0\, as [1]\,
a + y = 60\, as [2]\,
2a +  3f +  3q = 210\, as [3]\,

Substituting [1]\, in to [2]\,:

1(0) + y = 60\,
y = 60\, as [4]\,

Substituting [1]\, and [4]\,: in to [2]\,:

2(0) +  3(60) +  3q = 210\,
180 +  3q = 210\,
3q = 30\,
q = 10\,
a = 0\,, y = 60\,, q = 10\,