IIT JEE , AIEEE Forum - Mathematics , Algebra

preetirocks

1. If in a G.P, first term is a and common ratio is r, it's sum to infinity is 4 and the second term is 3/4, find the values of a and r
2. The no.of ways of dividing equally a pack of 52 cards among 4 players is ??
3. f(x) = logx/x is increasing on the interval?

deedee

2)

52!/(13!)^4

deedee

1)

second term is 3/4

ie

T2=3/4=a*r

sntill infnity =4=a/r-1

solvin them u'll get d ansewr

raulrag009

Q1

U get two eqn . solve them

$S_{\infty}=\frac{a}{1-r}=4\\\\ ar=\frac{3}{4}$

U get

$r=\frac{1}{4},\frac{3}{4}\\\\ a=3,1$

konichiwa2x

1)

substritue the value of a a into second equation to obtain the quadratic:

Solve

correspondingly,

raulrag009

Q3

narayana

1)

sum of infinity terms in g.p if r<1 is

a/1-r

a is first term

r is c.r

a/1-r=4

and ar=3/4

r=3/4a

a/1-3/4a=4

4a²-16a+12=0

a²-4a+3=0

a=1 or 3

so r is 3/4 or 1/4

konichiwa2x

for third question,

preetirocks

thanq very much

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