RAJASTHAN ­ PET Rajasthan PET Solved Paper-2005

  • question_answer
    If\[\frac{1}{q+r},\frac{1}{r+p},\frac{1}{p+q}\]are in AP, then

    A)  \[p,q,r\]will be in AP

    B)  \[\frac{1}{p},\frac{1}{q},\frac{1}{r}\]will be in AP

    C)  \[{{p}^{2}},{{q}^{2}},{{r}^{2}}\]will be in AP

    D)  \[\frac{1}{{{p}^{2}}},\frac{1}{{{q}^{2}}},\frac{1}{{{r}^{2}}}\]will be in AP

    Correct Answer: C

    Solution :

     If\[\frac{1}{q+r},\frac{1}{r+p},\frac{1}{p+q}\]are in AP. Then, \[\frac{1}{r+p}-\frac{1}{q+r}=\frac{1}{p+q}-\frac{1}{r+p}\] \[\Rightarrow \]\[\frac{q+r-r-p}{(r+p)(q+r)}=\frac{r+p-p-q}{(p+q)(r-p)}\] \[\Rightarrow \]\[\frac{(p-q)}{(q+r)}=\frac{(r-q)}{(p+q)}\] \[\Rightarrow \]\[(q-p)(q+p)=(r-q)(r+q)\] \[\Rightarrow \]\[{{q}^{2}}-{{p}^{2}}={{r}^{2}}-{{q}^{2}}\] \[\Rightarrow \]\[{{p}^{2}},{{q}^{2}},{{r}^{2}}\]are in AP.


You need to login to perform this action.
You will be redirected in 3 sec spinner