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Grade 12Algebra

solve the limits question given in attachment ..................................................................

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Profile image of Sarvesh
7 Years agoGrade 12
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1 Answer

Profile image of Aditya Gupta
7 Years ago
lim x tends to 1 (ax^2+bx+c)/(x – 1)^2 = 2
the denominator is tending to zero. so for this lim to exist, the numerator should also tend to zero else the limit would become infinite. so a(1)^2+b*1+c=0 or a+b+c=0 or c= -a-b
so we substitute value of c in (ax^2+bx+c)/(x – 1)^2 to get (ax^2+bx+c)/(x – 1)^2 = [a(x+1)+b]/(x-1). now for this lim to exist, numerator again should be zero since denom tends to zero.
so a(1+1)+b=0 or 2a+b=0.
so lim becomes  [a(x+1)+b]/(x-1)=  [a(x+1)-2a]/(x-1)= a
so a=2. similarly find b and c, and to find the limit (x-a)(x-b)(x-c)/(x+1) plug in those values and put x=1