Question

5 th question of rd sharma pls solve it(polynomials. ex2.1)

Answer 1

see..1/alph+1/beta = (alpha+beta)/alpha.beta....(by taking LCM)
so now ya can get the value of alpha+beta=1
&alpha.beta=-4
now...put this value into the above and you will get the answer.....!

Answer 2

Hey !!

solution :-

f(x) = x² - x - 4

•°•
$\alpha + \beta = - (b \div a)$

so , sum of roots = -(cofficient of x/cofficient of x²)

so ,
$\alpha + \beta = - ( - 1 \div 1) = 1$
------1)

and
$\alpha \times \beta = c \div a$

product of roots = constant term /cofficient of x²

hence ,
$\alpha \times \beta = - 4 \div 1$
= -4 ----------2)

now .from

from question ..

1/
$1 \div \alpha + 1 \div \beta - \alpha \times \beta$

=>
$\beta + \alpha \div \alpha \beta - \alpha \times \beta$

-1 /4 -4

=> 1 -16/4 = -15/4 Answer

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Hope it helps you !!!

@Rajukumar111