Find the limit... ?

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2 Answers
Jan 13, 2017

See Above

Jan 13, 2017

1/212

Explanation:

sqrt(9x^2+3x)-3x=(9x^2+3x-9x^2)/(sqrt(9x^2+3x)+3x)= (3x)/(sqrt(9x^2+3x)+3x)9x2+3x3x=9x2+3x9x29x2+3x+3x=3x9x2+3x+3x but

(3x)/(sqrt(9x^2+3x)+3x)=(3x)/(3x(sqrt(1+1/(3x))+1))=1/(sqrt(1+1/(3x))+1)3x9x2+3x+3x=3x3x(1+13x+1)=11+13x+1

finally

lim_(x->oo)sqrt(9x^2+3x)-3x=lim_(x->oo)1/(sqrt(1+1/(3x))+1)=1/2