Math, asked by daris52, 22 days ago

Without finding the zeroes a and B of
polynomial p (x) = 6x^2- 13x + 6, find the
values of the following:(i) 1/alpha+1/beta (ii) alpha^2+beta^2 (iii) alpha^3+beta^3 (iv) alpha/beta+beta/alpha​

Answers

Answered by ssritharina
2

Answer:  hi friend !

check the attachment

Step-by-step explanation: stay bless stay safe stay happy stay healthy be your self and be good

Attachments:
Answered by hukam0685
2

Step-by-step explanation:

Given:

p(x) = 6 {x}^{2}  - 13x + 6 \\

To find:

i) \frac{1}{ \alpha }  +  \frac{1}{ \beta }  \\  \\ ii) { \alpha }^{2}  +  { \beta }^{2}  \\  \\ iii) { \alpha }^{3}  +  { \beta }^{3}  \\  \\ iv) \frac{ \alpha }{ \beta }  +  \frac{ \beta }{ \alpha }  \\  \\

Solution:

If \alpha\:\:and\:\:\beta are zeros of quadratic polynomial ax^2+bx+c

then

 \alpha   + \beta  =  \frac{ - b}{a}  \\  \\  \alpha  \beta  =  \frac{c}{a} \\

According to the given quadratic polynomial

 \alpha +   \beta  =  \frac{13}{6} ...eq1 \\  \\   \alpha  \beta  = \frac{6}{6}  = 1...eq2 \\

i) Divide eq2 by eq1

 \frac{ \alpha  +  \beta }{ \alpha  \beta }  =  \frac{ \frac{13}{6} }{1}  \\  \\  \frac{\cancel\alpha }{\cancel \alpha  \beta }  +  \frac{\cancel \beta }{ \alpha \cancel\beta }  =  \frac{13}{6}  \\  \\  \frac{1}{ \beta }  +  \frac{1}{ \alpha }  =  \frac{13}{6}  \\  \\ or \\  \\  \frac{1}{ \alpha }  +  \frac{1}{ \beta }  =  \frac{13}{6}  \\  \\

ii) Square eq1

( { \alpha   + \beta )}^{2}  =  \frac{169}{36}  \\  \\ open \: whole \: square \\  \\  { \alpha }^{2}  +  { \beta }^{2}  + 2 \alpha  \beta  =  \frac{169}{36}  \\  \\ put \: value \: of \:  \alpha  \beta  \: from \: eq2 \\  \\  { \alpha }^{2}  +  { \beta }^{2} +2(1) = \frac{169}{36}\\\\{ \alpha }^{2}  +  { \beta }^{2}= \frac{169}{36}  - 2 \\  \\ { \alpha }^{2}  +  { \beta }^{2}  =  \frac{169 - 72}{36}   \\  \\ { \alpha }^{2}  +  { \beta }^{2}  =  \frac{97}{36}  \\  \\

iii) Take cube of eq1

 {( \alpha  +  \beta )}^{3}  = ( \frac{13}{6} )^{3}  \\  \\ open \: identity \: in \: left \: side \\  \\  { \alpha }^{3}  +  { \beta }^{3}  + 3 \alpha  \beta ( \alpha +   \beta ) =  \frac{2197}{216}  \\  \\ put \: value \: of \:  \alpha  +  \beta \: and \:   \alpha  \beta from \: eq1 \: and \: eq2 \\  \\ { \alpha }^{3}  +  { \beta }^{3}  + 3(1) \left( \frac{13}{6} \right ) =  \frac{2197}{216} \\  \\ { \alpha }^{3}  +  { \beta }^{3}=  \frac{2197}{216}  -  \frac{39}{6} \\  \\ { \alpha }^{3}  +  { \beta }^{3}=  \frac{2197 - 1404}{216}  \\  \\ { \alpha }^{3}  +  { \beta }^{3}=  \frac{793}{216}  \\  \\

iv)Divide result of (ii) by eq2

 \frac{ { \alpha }^{2} +  { \beta }^{2}  }{ \alpha  \beta }  =  \frac{97}{36}  \\  \\  \frac{ { \alpha }^{ \cancel2} }{  \cancel\alpha  \beta }  +  \frac{ { \beta }^{ \cancel2} }{ \alpha   \cancel\beta }  =  \frac{97}{36}  \\  \\  \frac{ \alpha }{ \beta }  +  \frac{ \beta }{ \alpha }  =  \frac{97}{36}  \\  \\

Final answer:

i) \green{\frac{1}{ \alpha }  +  \frac{1}{ \beta }  =  \frac{13}{6}}  \\

ii) \red{{ \alpha }^{2}  +  { \beta }^{2}  =  \frac{97}{36}}  \\

iii) \purple{{ \alpha }^{3}  +  { \beta }^{3}=  \frac{793}{216} }\\

iv)  \pink{\frac{ \alpha }{ \beta }  +  \frac{ \beta }{ \alpha }  =  \frac{97}{36} } \\

Hope it helps you.

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