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\displaystyle\red{\underline{\underline{Solution}}}

LET \displaystyle \:  \:  \alpha \:  \: and \:  \:  { \alpha}^{2}are the ROOTS of the equation \displaystyle \:  \:   {x}^{2}  + px + q = 0

Then

\displaystyle \:  \:  \alpha \:  +    { \alpha}^{2}  =  - p \:   \:  \: \: and \:  \:  \displaystyle \:  \:  \alpha \:   \times   \:  { \alpha}^{2}  = q

Which gives

\displaystyle \:  \:  \alpha (<klux>1</klux> +  { \alpha}) =  - p \:  \:  \:  \: .........(1)

\displaystyle \:  \:    \:  { \alpha}^{3}  = q \:  \:  \: ..........(2)

Now

Taking CUBE in both sides of (1)

\displaystyle \:  \:  {p}^{3}

=   - \displaystyle \:  \:    { \alpha}^{3} ({1 \:  \:  +  \:  \:  { \alpha})}^{3}

=   - \displaystyle \:  \:    { \alpha}^{3}  \{{1 \:  \:  +  \:  \:  { \alpha}}^{3}  + 3 { \alpha} {(1 +  \alpha})\}

\displaystyle \:  =  - q(1 + q  -  3p) \:  \: by \:  \: (1) \:  \:  \: and \:  \:  \: (2)

\displaystyle \:  =  - q -  {q}^{2}  + 3pq

So

\displaystyle \:  {p}^{3}  +  {q}^{2}  =  - q + 3pq

Hence

\displaystyle \:  {p}^{3}  +  {q}^{2}  =  q( 3p - 1)



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