frnds pls answer this question
maths class 10 polynomials
no spamming pls
answer asap
Answers
Solution:
Here I am using m,n instead of
Alfa and Beta.
Given m,n are zeroes of f(x)=x²-3x-2
Compare f(x) with ax²+bx+c,
we get
a = 1 , b = -3 , c=-2
i) m+n = -b/a = -(-3)/1=-3
ii) mn = c/a = (-2)/1 = -2
iii) m²+n² =(m+n)²-2mn
= (-3)²-2(-2)
= 9+4
= 13
Now,
If 1/(2m+n ) , 1/(2n+m)
are two zeroes ,
iv ) sum of the zeroes
= 1/(2m+n) + 1/(2n+m)
= [2n+m+2m+n]/[(2m+n)(2n+m)]
= [3m+3n]/[4mn+2m²+2n²+mn]
= [3(m+n)]/[5mn+2(m²+n²)]
= [3×(-3)]/[5(-2)+2×13]
= (-9)/[-10+26]
= (-9)/16
v) Product of the zeroes
= [1/(2m+n)][1/(2n+m)]
= 1/[(2m+n)(2n+m)]
= 1/[4mn+2m²+2n²+mn]
= 1/[5mn+2(m²+n²)]
= 1/[5(-2)+2×13]
= 1/(-10+26)
= 1/16
______________________
Form of quadratic polynomial
whose zeroes are p,q is
k[x²-(p+q)x+pq]
_____________________
Here,
Required polynomial is
k[ x² -(-9/16)x + (1/16)]
For real values of k , it is true.
Let k = 16, then
the polynomial is
16[ x²-(-9/16)x+1/16]
= 16x² +9x+1
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