Conceptual Doubt!! Differentiatuioin

Y = lim x2tan(1/x)/(√8x2 + 7x + 1)
x--> - ∞

Z = lim x2tan(1/x)/(√8x2 + 7x + 1)
x--> ∞

Find Y and Z

7 Answers

11
rkrish ·

Y = Z = 1/(2√2)

oops sorry [2][2]

1
avni ·

That was wat i too xpected but ans is = Z = - Y = 1/2√2

106
Asish Mahapatra ·

yup Y=-Z because if u consider cancelling the √x2 then u have to take it as lxl so it will be Y=-Z

1357
Manish Shankar ·

it should be Z=-Y=1/2√2

in Y put x=-y you will get something

1
avni ·

This was how i did for Y, pl. spot the mistake .......

let t = 1/x ----> 0

Y = (tant/t)/(√8 + 7p + 1)

Y = 1/2√2 ................. wer did i miss out the minus SIgn??

106
Asish Mahapatra ·

Y = \lim_{x->infinity}x*[tan(1/x)/(1/x)]/\sqrt{8x^2+7x+1}
Y = \lim_{x->infinity}x/\sqrt{8x^2+7x+1} = \lim_{x-> infinity}x/\left|x \right|\sqrt{8+7/x+1/x^2}

if.x->-infinity.. then..x/\left|x \right| = -1..

so it is Y=-1/2√2 and so Z=1/2√2 as in Z x/lxl = 1

sry in Y .. it shud have been x--> -∞ and i have written ∞ .. sry

1
avni ·

Oh okay..... tgnx asis

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