How is this M(2,2)->R closed under addition?












2














enter image description here



so I understand that It is closed under scalar multiplication, but how is it closed under addition? what if I add another matrix to A? and create new a,b,c,d values?










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  • 1




    "Closed under addition" is not quite the right phrase here. We use the properties of being closed under scalar multiplication and closed under addition to define vector spaces (with other properties), but the issue here is whether $T$ is a linear transformation, i.e. a mapping from one vector space to another that preserves operations of scalar multiplication and vector addition.
    – hardmath
    Dec 17 at 23:50










  • ohhh okay thank you that clarified that for me
    – isuckatprogramming
    Dec 18 at 1:15
















2














enter image description here



so I understand that It is closed under scalar multiplication, but how is it closed under addition? what if I add another matrix to A? and create new a,b,c,d values?










share|cite|improve this question


















  • 1




    "Closed under addition" is not quite the right phrase here. We use the properties of being closed under scalar multiplication and closed under addition to define vector spaces (with other properties), but the issue here is whether $T$ is a linear transformation, i.e. a mapping from one vector space to another that preserves operations of scalar multiplication and vector addition.
    – hardmath
    Dec 17 at 23:50










  • ohhh okay thank you that clarified that for me
    – isuckatprogramming
    Dec 18 at 1:15














2












2








2







enter image description here



so I understand that It is closed under scalar multiplication, but how is it closed under addition? what if I add another matrix to A? and create new a,b,c,d values?










share|cite|improve this question













enter image description here



so I understand that It is closed under scalar multiplication, but how is it closed under addition? what if I add another matrix to A? and create new a,b,c,d values?







linear-algebra






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asked Dec 17 at 23:39









isuckatprogramming

256




256








  • 1




    "Closed under addition" is not quite the right phrase here. We use the properties of being closed under scalar multiplication and closed under addition to define vector spaces (with other properties), but the issue here is whether $T$ is a linear transformation, i.e. a mapping from one vector space to another that preserves operations of scalar multiplication and vector addition.
    – hardmath
    Dec 17 at 23:50










  • ohhh okay thank you that clarified that for me
    – isuckatprogramming
    Dec 18 at 1:15














  • 1




    "Closed under addition" is not quite the right phrase here. We use the properties of being closed under scalar multiplication and closed under addition to define vector spaces (with other properties), but the issue here is whether $T$ is a linear transformation, i.e. a mapping from one vector space to another that preserves operations of scalar multiplication and vector addition.
    – hardmath
    Dec 17 at 23:50










  • ohhh okay thank you that clarified that for me
    – isuckatprogramming
    Dec 18 at 1:15








1




1




"Closed under addition" is not quite the right phrase here. We use the properties of being closed under scalar multiplication and closed under addition to define vector spaces (with other properties), but the issue here is whether $T$ is a linear transformation, i.e. a mapping from one vector space to another that preserves operations of scalar multiplication and vector addition.
– hardmath
Dec 17 at 23:50




"Closed under addition" is not quite the right phrase here. We use the properties of being closed under scalar multiplication and closed under addition to define vector spaces (with other properties), but the issue here is whether $T$ is a linear transformation, i.e. a mapping from one vector space to another that preserves operations of scalar multiplication and vector addition.
– hardmath
Dec 17 at 23:50












ohhh okay thank you that clarified that for me
– isuckatprogramming
Dec 18 at 1:15




ohhh okay thank you that clarified that for me
– isuckatprogramming
Dec 18 at 1:15










2 Answers
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Help me fill this in:



begin{align*}
T begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} &= underline{hspace{50pt}} in mathbb{R} \
T begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix} &= underline{hspace{50pt}} in mathbb{R} \
T begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} +T begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix} &= underline{hspace{50pt}} in mathbb{R} \
begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} + begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix} &= underline{hspace{50pt}} in M_{2, 2} \
Tleft(begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} + begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix}right) &= underline{hspace{50pt}} in mathbb{R}.
end{align*}

Are your answers to questions 3 and 5 the same? If so, then $T$ is additive. You can try a similar tactic with scalar multiplication. Let me know with a comment if you want further help.






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    0














    TIP: the sum of two matrices is a matrix. Try writing $T(A)$ in terms of the values of this matrix and, after expanding each term (because they're bound on the other two matrices), compare the final expression two the other two expressions.






    share|cite|improve this answer





















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      2 Answers
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      2 Answers
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      6














      Help me fill this in:



      begin{align*}
      T begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} &= underline{hspace{50pt}} in mathbb{R} \
      T begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix} &= underline{hspace{50pt}} in mathbb{R} \
      T begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} +T begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix} &= underline{hspace{50pt}} in mathbb{R} \
      begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} + begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix} &= underline{hspace{50pt}} in M_{2, 2} \
      Tleft(begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} + begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix}right) &= underline{hspace{50pt}} in mathbb{R}.
      end{align*}

      Are your answers to questions 3 and 5 the same? If so, then $T$ is additive. You can try a similar tactic with scalar multiplication. Let me know with a comment if you want further help.






      share|cite|improve this answer


























        6














        Help me fill this in:



        begin{align*}
        T begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} &= underline{hspace{50pt}} in mathbb{R} \
        T begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix} &= underline{hspace{50pt}} in mathbb{R} \
        T begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} +T begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix} &= underline{hspace{50pt}} in mathbb{R} \
        begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} + begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix} &= underline{hspace{50pt}} in M_{2, 2} \
        Tleft(begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} + begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix}right) &= underline{hspace{50pt}} in mathbb{R}.
        end{align*}

        Are your answers to questions 3 and 5 the same? If so, then $T$ is additive. You can try a similar tactic with scalar multiplication. Let me know with a comment if you want further help.






        share|cite|improve this answer
























          6












          6








          6






          Help me fill this in:



          begin{align*}
          T begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} &= underline{hspace{50pt}} in mathbb{R} \
          T begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix} &= underline{hspace{50pt}} in mathbb{R} \
          T begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} +T begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix} &= underline{hspace{50pt}} in mathbb{R} \
          begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} + begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix} &= underline{hspace{50pt}} in M_{2, 2} \
          Tleft(begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} + begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix}right) &= underline{hspace{50pt}} in mathbb{R}.
          end{align*}

          Are your answers to questions 3 and 5 the same? If so, then $T$ is additive. You can try a similar tactic with scalar multiplication. Let me know with a comment if you want further help.






          share|cite|improve this answer












          Help me fill this in:



          begin{align*}
          T begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} &= underline{hspace{50pt}} in mathbb{R} \
          T begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix} &= underline{hspace{50pt}} in mathbb{R} \
          T begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} +T begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix} &= underline{hspace{50pt}} in mathbb{R} \
          begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} + begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix} &= underline{hspace{50pt}} in M_{2, 2} \
          Tleft(begin{pmatrix}a_1 & b_1 \ c_1 & d_1 end{pmatrix} + begin{pmatrix}a_2 & b_2 \ c_2 & d_2 end{pmatrix}right) &= underline{hspace{50pt}} in mathbb{R}.
          end{align*}

          Are your answers to questions 3 and 5 the same? If so, then $T$ is additive. You can try a similar tactic with scalar multiplication. Let me know with a comment if you want further help.







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Dec 17 at 23:57









          Theo Bendit

          16.3k12148




          16.3k12148























              0














              TIP: the sum of two matrices is a matrix. Try writing $T(A)$ in terms of the values of this matrix and, after expanding each term (because they're bound on the other two matrices), compare the final expression two the other two expressions.






              share|cite|improve this answer


























                0














                TIP: the sum of two matrices is a matrix. Try writing $T(A)$ in terms of the values of this matrix and, after expanding each term (because they're bound on the other two matrices), compare the final expression two the other two expressions.






                share|cite|improve this answer
























                  0












                  0








                  0






                  TIP: the sum of two matrices is a matrix. Try writing $T(A)$ in terms of the values of this matrix and, after expanding each term (because they're bound on the other two matrices), compare the final expression two the other two expressions.






                  share|cite|improve this answer












                  TIP: the sum of two matrices is a matrix. Try writing $T(A)$ in terms of the values of this matrix and, after expanding each term (because they're bound on the other two matrices), compare the final expression two the other two expressions.







                  share|cite|improve this answer












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                  share|cite|improve this answer










                  answered Dec 17 at 23:44









                  Lucas Henrique

                  725313




                  725313






























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