IIT JEE , AIEEE Forum - Mathematics , Differential Calculus - derivative wrt x of (1-2x+3x*2-4x*3+........) when |x|<1 is? How?ans is:-2(1+x)*-3

payal1spark

derivative wrt x of (1-2x+3x*2-4x*3+........) when |x|<1 is? How?ans is:-2(1+x)*-3

chinnu

let S=1-2x+

now S(x)=x-2x^2+3x^3......

add the two eqns

S(1+x)=

S= (G.P. a<1)

ds/dx=

riku

i liked d pic.. nyways wats d answer u have written

is it:::

2(1+x)-3

or $2{(1+x)}^{-3}$

m gettin it second one..

riku

v hav already got d ans.. good.. its rite...

payal1spark

its -2 (1+x) raised to -3
n thanks yaar...