Find (AB)–1 if  from Mathematics Determinants

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 Multiple Choice QuestionsLong Answer Type

191.

If straight A space equals open square brackets table row 2 cell space space space space space space space 3 end cell row 1 cell space space minus 4 end cell end table close square brackets comma space straight B space equals space open square brackets table row cell space space space 1 end cell cell space space space space minus 2 end cell row cell negative 1 end cell cell space space space space space space 3 end cell end table close square brackets comma
verify that (AB)–1 = B–1 A–1

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192.

Let straight A space equals space open square brackets table row 3 cell space space space 7 end cell row 2 cell space space 5 end cell end table close square brackets space and space straight B space equals space open square brackets table row 6 cell space space 8 end cell row 7 cell space space 9 end cell end table close square brackets comma verify that (AB)–1 = B–1 A–1.

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193. Verify that (AB)–1 = B–1 A–1 for the matrices A and B where straight A space equals space open square brackets table row 3 cell space space 2 end cell row 7 cell space space 5 end cell end table close square brackets comma space space straight B space equals space open square brackets table row 4 cell space space 6 end cell row 3 cell space space 2 end cell end table close square brackets
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194. Verify that (AB)–1 = B–1 A–1 for the matrices A and B where straight A space equals open square brackets table row 3 cell space space 2 end cell row 7 cell space space 5 end cell end table close square brackets comma space space straight B space equals space open square brackets table row 6 cell space space space space 7 end cell row 8 cell space space space space 9 end cell end table close square brackets.

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195. Verify that (AB)–1 = B–1 A–1 for the matrices A and B where straight A space equals space open square brackets table row 2 cell space space space 1 end cell row 5 cell space space space 3 end cell end table close square brackets comma space space space straight B space equals space open square brackets table row 4 cell space space space 5 end cell row 3 cell space space 4 end cell end table close square brackets.

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 Multiple Choice QuestionsShort Answer Type

196.

Find (AB)–1 if straight A space equals space open square brackets table row 3 cell space 4 end cell row 1 cell space 1 end cell end table close square brackets comma space space straight B to the power of negative 1 end exponent space equals space open square brackets table row 4 cell space space 3 end cell row 2 cell space space 1 end cell end table close square brackets

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197.

Find (AB)–1 if straight A space equals space open square brackets table row 5 cell space space 0 end cell row 2 cell space space space 3 end cell end table close square brackets comma space space space straight B to the power of negative 1 end exponent space equals space open square brackets table row 1 cell space space space 2 end cell row 1 cell space space 4 end cell end table close square brackets


Here straight A space equals open square brackets table row 5 cell space 0 end cell row 2 cell space 3 end cell end table close square brackets comma space space straight B to the power of negative 1 end exponent space equals space open square brackets table row 1 cell space space 2 end cell row 1 cell space space 4 end cell end table close square brackets space space

    open vertical bar straight A close vertical bar space equals space open vertical bar table row 5 cell space space 0 end cell row 2 cell space space 3 end cell end table close vertical bar space equals space 15 minus 0 space equals space 15
rightwards double arrow space space space space straight A to the power of negative 1 end exponent space exists. space
Co-factors of elements of first row of | A | are 3, – 2 respectively.
Co-factors of elements of second row of | A | are 0, 5 respectively.
therefore space space space space adj. space straight A space equals space open square brackets table row 3 cell space space minus 2 end cell row 0 cell space space space space 5 end cell end table close square brackets to the power of apostrophe space equals space open square brackets table row cell space space 3 end cell cell space space space 0 end cell row cell negative 2 end cell cell space space space 5 end cell end table close square brackets
therefore space space space space space space space space straight A to the power of negative 1 end exponent space equals space fraction numerator adj space straight A over denominator open vertical bar straight A close vertical bar end fraction space equals space 1 over 15 open square brackets table row cell space space 3 end cell cell space space space 0 end cell row cell negative 2 end cell cell space space space 5 end cell end table close square brackets
space space space space space left parenthesis AB right parenthesis to the power of negative 1 end exponent space equals space straight B to the power of negative 1 end exponent straight A to the power of negative 1 end exponent space equals space 1 over 15 open square brackets table row 1 cell space space 2 end cell row 1 cell space space 4 end cell end table close square brackets space open square brackets table row cell space space space 3 end cell cell space space space 0 end cell row cell negative 2 end cell cell space space space 5 end cell end table close square brackets space equals space 1 over 15 open square brackets table row cell 3 minus 4 end cell cell space space space 0 plus 10 end cell row cell 3 minus 8 end cell cell space space space space 0 plus 20 end cell end table close square brackets
space space space space space space space space space space space space space space space space space space space equals space 1 over 15 open square brackets table row cell negative 1 end cell cell space space space 10 end cell row cell negative 5 end cell cell space space 20 end cell end table close square brackets

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 Multiple Choice QuestionsLong Answer Type

198.

Find the inverse of the matrix
straight A space equals space open square brackets table row cell negative 1 end cell cell space space 1 end cell cell space space 2 end cell row cell space space space 3 end cell cell negative 1 end cell cell space space 1 space end cell row cell space minus 1 end cell cell space space 3 end cell cell space 4 end cell end table close square brackets.

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199. Find the inverse of the matrix:
open square brackets table row 1 cell space space space minus 1 end cell cell space space space space space space 2 end cell row 0 cell space space space space space space 2 end cell cell space space space minus 3 end cell row 3 cell space space space minus 2 end cell cell space space space space space space 4 end cell end table close square brackets.
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200.

If straight A space equals space open square brackets table row 0 cell space space space 0 end cell cell space space 1 end cell row 0 cell space space 1 end cell cell space space 0 end cell row 1 cell space space 0 end cell cell space space 0 end cell end table close square brackets comma show that  A–1 = A.

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