IXL - Identify inverse matrices (Precalculus practice)

Are

–

and

–

multiplicative inverses?

yes

ref_doc_title.

Learn with an example

question

Are

–

and

–

multiplicative inverses?

yes

key idea

The

identity matrix

has 1's on its diagonal (upper left to lower right) and 0's elsewhere. For example:

and

are

matrices and

then

is the multiplicative inverse of

written

–

To find the element in the

𝑖

^th

row and

^th

column of the product of two matrices, multiply each element in the

𝑖

^th

row of the first matrix by the corresponding element in the

^th

column of the second matrix. Then add the products.

solution

If the matrices multiply to the identity matrix

both ways, they are multiplicative inverses.

Multiply the matrices one way.

–

(

)

(

–

)

–

(

–

)

(

)

–

Since the matrices do not multiply to

they are not multiplicative inverses.

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Q.6Multiply two matrices

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