Why is the calculator giving me different answers???












0












$begingroup$


I have a question with regards to calculating annuity due in terms of annuity immediate.



I thought that one way to do so is annuity due for n periods = annuity immediate n-1 periods + 1 (where the payment is 1). However, I did this for a part of a problem that is basically
Present value is 500,000 of a 10 year annuity due of X. Interest rate is 9% annual effective. Calculate X. Why doesn’t the following work??



PV of annuity due of 10 years of payment 1 = annuity immediate of 9 years of payment 1 + 1
Then divide 500,000 by the right hand side of this equation?



When I do this, I get PV = 7 from the calculator, so payment is 500,000/7. But when I do another method, I get a lower answer, which is the right answer according to the manual. But I don’t understand why they should be different.



The other method is PV of annuity due of n years = (1 + i) * PV annuity immediate of n years. This gives the correct answer. >.<



Sorry if I’ve misunderstood something fundamental and thank you in advance for the help!










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  • $begingroup$
    Please also show the other method.
    $endgroup$
    – Peter
    Jan 11 at 14:35










  • $begingroup$
    It’s edited now, thanks!
    $endgroup$
    – quietkid
    Jan 11 at 14:48










  • $begingroup$
    @quietkid Since you know how to use MathJax I would recommend to write the equations in Mathjax. At the moment it is not clear which equations you´re talking about.
    $endgroup$
    – callculus
    Jan 11 at 17:51


















0












$begingroup$


I have a question with regards to calculating annuity due in terms of annuity immediate.



I thought that one way to do so is annuity due for n periods = annuity immediate n-1 periods + 1 (where the payment is 1). However, I did this for a part of a problem that is basically
Present value is 500,000 of a 10 year annuity due of X. Interest rate is 9% annual effective. Calculate X. Why doesn’t the following work??



PV of annuity due of 10 years of payment 1 = annuity immediate of 9 years of payment 1 + 1
Then divide 500,000 by the right hand side of this equation?



When I do this, I get PV = 7 from the calculator, so payment is 500,000/7. But when I do another method, I get a lower answer, which is the right answer according to the manual. But I don’t understand why they should be different.



The other method is PV of annuity due of n years = (1 + i) * PV annuity immediate of n years. This gives the correct answer. >.<



Sorry if I’ve misunderstood something fundamental and thank you in advance for the help!










share|cite|improve this question











$endgroup$












  • $begingroup$
    Please also show the other method.
    $endgroup$
    – Peter
    Jan 11 at 14:35










  • $begingroup$
    It’s edited now, thanks!
    $endgroup$
    – quietkid
    Jan 11 at 14:48










  • $begingroup$
    @quietkid Since you know how to use MathJax I would recommend to write the equations in Mathjax. At the moment it is not clear which equations you´re talking about.
    $endgroup$
    – callculus
    Jan 11 at 17:51
















0












0








0





$begingroup$


I have a question with regards to calculating annuity due in terms of annuity immediate.



I thought that one way to do so is annuity due for n periods = annuity immediate n-1 periods + 1 (where the payment is 1). However, I did this for a part of a problem that is basically
Present value is 500,000 of a 10 year annuity due of X. Interest rate is 9% annual effective. Calculate X. Why doesn’t the following work??



PV of annuity due of 10 years of payment 1 = annuity immediate of 9 years of payment 1 + 1
Then divide 500,000 by the right hand side of this equation?



When I do this, I get PV = 7 from the calculator, so payment is 500,000/7. But when I do another method, I get a lower answer, which is the right answer according to the manual. But I don’t understand why they should be different.



The other method is PV of annuity due of n years = (1 + i) * PV annuity immediate of n years. This gives the correct answer. >.<



Sorry if I’ve misunderstood something fundamental and thank you in advance for the help!










share|cite|improve this question











$endgroup$




I have a question with regards to calculating annuity due in terms of annuity immediate.



I thought that one way to do so is annuity due for n periods = annuity immediate n-1 periods + 1 (where the payment is 1). However, I did this for a part of a problem that is basically
Present value is 500,000 of a 10 year annuity due of X. Interest rate is 9% annual effective. Calculate X. Why doesn’t the following work??



PV of annuity due of 10 years of payment 1 = annuity immediate of 9 years of payment 1 + 1
Then divide 500,000 by the right hand side of this equation?



When I do this, I get PV = 7 from the calculator, so payment is 500,000/7. But when I do another method, I get a lower answer, which is the right answer according to the manual. But I don’t understand why they should be different.



The other method is PV of annuity due of n years = (1 + i) * PV annuity immediate of n years. This gives the correct answer. >.<



Sorry if I’ve misunderstood something fundamental and thank you in advance for the help!







finance actuarial-science






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share|cite|improve this question













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edited Jan 11 at 14:48







quietkid

















asked Jan 11 at 14:27









quietkidquietkid

415




415












  • $begingroup$
    Please also show the other method.
    $endgroup$
    – Peter
    Jan 11 at 14:35










  • $begingroup$
    It’s edited now, thanks!
    $endgroup$
    – quietkid
    Jan 11 at 14:48










  • $begingroup$
    @quietkid Since you know how to use MathJax I would recommend to write the equations in Mathjax. At the moment it is not clear which equations you´re talking about.
    $endgroup$
    – callculus
    Jan 11 at 17:51




















  • $begingroup$
    Please also show the other method.
    $endgroup$
    – Peter
    Jan 11 at 14:35










  • $begingroup$
    It’s edited now, thanks!
    $endgroup$
    – quietkid
    Jan 11 at 14:48










  • $begingroup$
    @quietkid Since you know how to use MathJax I would recommend to write the equations in Mathjax. At the moment it is not clear which equations you´re talking about.
    $endgroup$
    – callculus
    Jan 11 at 17:51


















$begingroup$
Please also show the other method.
$endgroup$
– Peter
Jan 11 at 14:35




$begingroup$
Please also show the other method.
$endgroup$
– Peter
Jan 11 at 14:35












$begingroup$
It’s edited now, thanks!
$endgroup$
– quietkid
Jan 11 at 14:48




$begingroup$
It’s edited now, thanks!
$endgroup$
– quietkid
Jan 11 at 14:48












$begingroup$
@quietkid Since you know how to use MathJax I would recommend to write the equations in Mathjax. At the moment it is not clear which equations you´re talking about.
$endgroup$
– callculus
Jan 11 at 17:51






$begingroup$
@quietkid Since you know how to use MathJax I would recommend to write the equations in Mathjax. At the moment it is not clear which equations you´re talking about.
$endgroup$
– callculus
Jan 11 at 17:51












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$begingroup$

You cannot have different results, because



$$
ddot a_{overline{n} |i} =a_{overline{n-1} |i}+i=frac{1-(1+i)^{-(n-1)}}{i} +1=frac{1+i-(1+i)^{-n+1}}{i}=(1+i) frac{1-(1+i)^{-n}}{i}=(1+i)a_{overline{n} |i}
$$






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    1 Answer
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    1 Answer
    1






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    $begingroup$

    You cannot have different results, because



    $$
    ddot a_{overline{n} |i} =a_{overline{n-1} |i}+i=frac{1-(1+i)^{-(n-1)}}{i} +1=frac{1+i-(1+i)^{-n+1}}{i}=(1+i) frac{1-(1+i)^{-n}}{i}=(1+i)a_{overline{n} |i}
    $$






    share|cite|improve this answer









    $endgroup$


















      1












      $begingroup$

      You cannot have different results, because



      $$
      ddot a_{overline{n} |i} =a_{overline{n-1} |i}+i=frac{1-(1+i)^{-(n-1)}}{i} +1=frac{1+i-(1+i)^{-n+1}}{i}=(1+i) frac{1-(1+i)^{-n}}{i}=(1+i)a_{overline{n} |i}
      $$






      share|cite|improve this answer









      $endgroup$
















        1












        1








        1





        $begingroup$

        You cannot have different results, because



        $$
        ddot a_{overline{n} |i} =a_{overline{n-1} |i}+i=frac{1-(1+i)^{-(n-1)}}{i} +1=frac{1+i-(1+i)^{-n+1}}{i}=(1+i) frac{1-(1+i)^{-n}}{i}=(1+i)a_{overline{n} |i}
        $$






        share|cite|improve this answer









        $endgroup$



        You cannot have different results, because



        $$
        ddot a_{overline{n} |i} =a_{overline{n-1} |i}+i=frac{1-(1+i)^{-(n-1)}}{i} +1=frac{1+i-(1+i)^{-n+1}}{i}=(1+i) frac{1-(1+i)^{-n}}{i}=(1+i)a_{overline{n} |i}
        $$







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 12 at 1:20









        alexjoalexjo

        12.5k1430




        12.5k1430






























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