IIT JEE , AIEEE Forum - Mathematics , Differential Calculus

manjotpahwa

If x is so small that x3 and higher powers of x may be neglected, then

may be approximated as

ashish_banga

manjotpahwa

thats wat i got but thats not the correct ans

manjotpahwa

help out

manjotpahwa

anyone please!!!!!!!!!

Pavis

put x=2sin2

Aatish

I m getting answer as $\frac{-3}{8} x^2$

see how.......

on expanding.... $( 1 + x ) ^ \frac{3}{2}$ after neglecting x^3

and higher powers.....
$1 + \frac{3}{2} x + \frac{3}{8} x^2$ --------------- ( 1 )

similarly expanding.... $( 1 + \frac{x}{2} ) ^3$
we get...
$1 + \frac{3}{2} x + \frac{3}{4} x^2$ ------------------( 2 )

and expanding....... $( 1 - x ) ^\frac{-1}{2}$ we get....
$1 + \frac{1}{2} x + \frac{3}{8} x^2$ --------------------( 3 )

NOW in question we have [ ( 1 ) - ( 2 ) ] * ( 3 )

where again neglecting x^3

and higher powers of x.......we get........

$\frac{-3}{8} x^2$

spideyunlimited

solving......

sweet08

-3x^2/8

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