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Catalogs Discussion Forums -> Trignometry -> the radii r1,r2,r3 of escribed circles of triangle ABC are in harmonic progression. If its area is 2 -> Go to message
This Post 10 points    (Olaaa!! Perrrfect answer.   in 2 votes )   [?]

Let the sides be a , b ,c

r1=S/(s-a)   ...r2=S/(s-b).........r3=S/(s-c)

As these r in HP

2 / r2 = 1/ r1  + 1/r3

putting the values we will get " b = 8 " and a +c = 16

so tan B = 4 / 3

by Area the height on "b" should be 6

by seeing the value of tan B 

a = 10 ,b =8,c=6

or

a=6,b=8 ,c=10

 

 

Catalogs Discussion Forums -> Integral Calculus -> Loading..Definte integration -> Go to message
This Post 2 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]

i m in a hurry so just giving answer to 1st one .

int ( -3 to -1 ) (x+1)(x+2)(x+3) dx

Transformation x+2 =y

=int (-1 to 1 ) (y-1) y (y+1)dy

= 0

Catalogs Discussion Forums -> Differential Calculus -> evaluate..lim x tends to 0 [sinx/x] [ ] represents greatest integer function... -> Go to message
This Post 2 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]

limx--->0 sin(x)/x is 1 .

But actually sin(x) <x

so the ratio would tend to 1 or we can say its GIF is 0

Thank u

Catalogs Discussion Forums -> Algebra -> find the last 2 digits of 7^(7^1000) -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]

71000 = (50-`1)500=500C0 50500-.......................................-500*50+1

=1000(k)+1

ab dekh 7 ki powers ke unit digit periodic hain 4 ke . e.g . 7 , 49 , 243 ,2401,then again 16807 

So u can say without any doubt that unit digit of 77^(1000) would be 7 .

7 1000k+1 =7 ( 71000k) = 7 ( 50 -1)500k =7.(500kC050500k-................-500*50k+1)

all the first 500k numbers would be having atleast 3 zero on the last three places . 07 would be last two digit 

Suggestion ::

Yaar have a knowlegde of number theory . It helps a lot .

Thank u

 

Catalogs Discussion Forums -> Differential Calculus -> pls explain how 2 draw the graph of {sinx}..fractional part of sinx... -> Go to message
This Post 10 points    (Olaaa!! Perrrfect answer.   in 2 votes )   [?]

We just need to concentrate again on a period only let it be x belonging to 0 to 2pi

Now from x =0 to x=pi/2

everywhere sinx is less than 1 so graph would be same as sin(x) but on x=pi/2 sinx becomes 1 so every comes first point of disconcounity {sin(pi/2)}=0

again after x=pi/2 to x =pi

graph would be same as sin(x)

Then from x =pi to x=2pi ( excluding these points )

sin(x) lie b/w 0 and (-1) so its Greatest integer part would be (-1)

So just add 1 to the graph or in easier way uplift the graph to 1 unit .

Repeat the pattern further on .

Thank u

Catalogs Discussion Forums -> Integral Calculus -> plz solve these integrals -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
http://www.goiit.com/posts/list/integral-calculus-indefinte-integration-reloaded-998418.htm
Catalogs Discussion Forums -> Integral Calculus -> Indefinte integration reloaded -> Go to message
This Post 7 points    (Olaaa!! Perrrfect answer.   in 2 votes )   [?]

2. using integration by parts

I = x log (Sqrt(1-x)+sqrt(1+x)) - integration ( ( 1-Sqrt(1-x2)) /( -2Sqrt(1-x2)) dx

= x log (Sq.(1-x)+Sq (1+x)) - 1/2 ( integration ( 1 - (1/Sqrt(1-x2 )) dx )

= x log (Sq.(1-x)+Sq (1+x))- x/2 +sin-1(x)/2 +constant

thank  u

Catalogs Discussion Forums -> Analytical Geometry -> A quadrilateral has sides 2,3,9....diagonals are at rt.angles. Find all possible values of -> Go to message
This Post 2 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]

Catalogs Discussion Forums -> Analytical Geometry -> A quadrilateral has sides 2,3,9....diagonals are at rt.angles. Find all possible values of -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]

Check d figure ::

either CD would be of 9 length or CB .

Case I :: when BC=9

AS AC is perpendicular to BD

In triangle

AOD

p2+q2=4

In tri. AOB

q2+r2=9

Also in triangle BOC

s2+r2 =81

using eq. I and III in II

gives

p2+s2 =76 =CD2

CD=sqrt(76 )

Case II

CD=9

repeat the above method

BC =sqrt(86)

thank u

 

Catalogs Discussion Forums -> Integral Calculus -> int x^2 / ( xsinx+cosx)^2 -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]

well

2 nd method This way is my way to solve this

look

(x sin(x)+cos(x) ) = Sqrt(1 +x2 ) cos( x -tan-1(x))

so ur question become

int ( x2 sec2 (x -tan-1x ))/(1+x2) dx

put x-tan^(-1)x = t

x2/(1+x2)dx =dt

= int sec^2 t dt

= tan (x -tan-1(x)) +C

thank u

Catalogs Discussion Forums -> Integral Calculus -> int x^2 / ( xsinx+cosx)^2 -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]

hi

 i have 2 method

1st method

I = integration ( x sec(x) x cos(x)/(xsinx +cos(x))2 dx

integration by parts

=x sec(x) int ( xcosx /(xsinx +cos(x))2 dx) - int [  (  xsecxtanx+secx) int (xsinx +cos(x))2 ]dx

= -xsecx / ( xsinx+cosx) + int (sec^2x)dx

= -xsecx / ( xsinx+cosx) +tanx +c

thank u

 

Catalogs Discussion Forums -> Integral Calculus -> Questions -> Go to message
This Post 2 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]

2 . lim ( n --> infty) (1/n) [ ( 1/ n+1) + (2 / n+2) + .......... + (3n/4n) ]

=lim ( n --> infty) (1/n) (1/(n+1) +1/(n/2 +1)+....................+1/(n/3n+1) ] 

= lim ( n --> infty) (1/n) sigma ( r from 1 to 3n ) [ 1/(n/r +1) ]

= integration ( 0 to 3 ) x / (x+1) dx            ( put r/n =x )

=x - log (x+1)

after putting limits

=3-log(4) 

thank u

Catalogs Discussion Forums -> Differential Calculus -> DOMAIN -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

thank to Jesus , atleast there is one who know kabi is a gal not a bhai sahab .

Catalogs Discussion Forums -> Differential Calculus -> DOMAIN -> Go to message
This Post 2 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]

hello

is it greatest integer of mode x   or greatest integer of x  ?

If greatest integer of mode x ::

-3=<[IxI]=<2

-3=< IxI < 3

we know IxI>=0 always

so inequality becomes ::

0=< IxI <3

so -3 <x<3 is the solution

if it is greatest integer of x only

-3=<[x] <=2

-3=<x<3 will be d solution 

b. f([2x+3])

-3<=[2x+3]<=2

-3<=2x+3 <3

-3<=x<0 is d solution .

thank u

 

Catalogs Discussion Forums -> Differential Calculus -> maximum & minimum value -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
Is not FTSE Part 1 question ? Don't u have the solution booklet or u r asking for the alternate methods other than the one discussed in the booklet .
Catalogs Discussion Forums -> Analytical Geometry -> find the range of parameter a fr which the variable line y=2x+a lies btw the circle x(sqr)+y(sqr -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]

hello

i m not going to solve this prob just giving the approach

first of all draw the circles so that u can actually visualise where a should lie .

we want y = 2x+a neither to touch the circles nor intersect any of them

put y = 2x +a in the eq. x2+y2-2x-2y+1 =0

u will get

5x2 +4xa -6x+a2 -2a +1 =0

for fulfilling the condition we want the  d < 0 of this quadractic

so a2+2a -4 >0

solve this a >sqrt(5)-1 or a < - (sqrt(5)+1)

if we want such value of a so that lie b/w the circles u can easily come to conclusion

we want a < - (sqrt(5)+1) only . 

then do the same thing for second circle . and find the value of a . ask me again if u have prob.

 

Catalogs Discussion Forums -> Analytical Geometry -> Q 1 :Find the locus of the middle points of the intercepts made by the axes on the lines drawn t -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]

hello

we have D ( 20,25) E ( 8,16) C( 10,15 )

slope of AC = -1/2

slope of BC = 1

Thus slope of BE = 2 and that of AD = -1

thus the eq. of AD becomes y +x = 45

eq. of BE  is y = 2x

the point of concurrency is x = 15 y=30 ie. coordinate of orthocenter .

thank u sorry if there is a calculation mistake as i m solving in hurry . 

one more thing the approach used by the student who have given the second answer is correct . 

Catalogs Discussion Forums -> Integral Calculus -> DIFFERENTIAL EQUATION CHALLENGE 3 -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

i would say " Samajdar ko ishara kafi "

Catalogs Discussion Forums -> Integral Calculus -> DIFFERENTIAL EQUATION CHALLENGE 3 -> Go to message
This Post 12 points    (Olaaa!! Perrrfect answer.   in 3 votes )   [?]

well here we say thanks by giving rates .

Catalogs Discussion Forums -> Algebra -> If f(x) is a function satisfying f -> Go to message
This Post 7 points    (Olaaa!! Perrrfect answer.   in 2 votes )   [?]

first of all this is a wrong forum for ur question ::

I =integration( sin @ to cosec@ ) f(x) dx.................(1)

let x =1/y

I = integration ( cosec@ to sin@ ) -f (y)dy /y2   ( we know from relation f(y) = - f(1/y) / y2

= integration ( sin@ to cosec@ ) -f(y) dy

integration ( sin@ to cosec@ ) -f(x) dx .................(2)

adding 1 and 2

I = 0

thank u

 

 

 
 
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