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

Check the graph below, i think that will give you all the answer.

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

Draw the line y=-x

and on that line draw sin2x graph, this is what your graph would exactly be.

Catalogs Discussion Forums -> Algebra -> Range of the function -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

As you know, mode always give a positive value. so, |2x-5| at min can be zero.

So, max value possible is 2.

and ofcourse, the |2x-5| can result into infinity. So, -infinity is lower limit.

Range: (-infinity, 2]

Catalogs Discussion Forums -> Algebra -> On differentiating y = 3x we get the result as 3x(log3). How do we get log3 in there? Please exp -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

it's easy to analyze.

Whenever, you have variables in exponent, simply take log to ease your headache.

so, taking log:

log y = x*log3.

now, diff

(1/y) dy/dx = log3.

now, is it clear from where log3 came into picture :)

Catalogs Discussion Forums -> Algebra -> how is lny =x ln3 on differentiating become ..1/y dy/dx=ln3 ..?! -> Go to message
This Post 7 points    (Olaaa!! Perrrfect answer.   in 2 votes )   [?]

ok, apply product rule on right side, you'll still get the same ans.

you have x*ln3.

diff it as per product rule:  x*(d(ln3)/dx) + ln3 (dx/dx)

As, ln3 is a constant. So, it's diff. will be zero.

So, we are left with ln3 only.

Hope it's clear now.

Feel free to ask/nudge.

Catalogs Discussion Forums -> Differential Calculus -> if f(sinx)=f(cosx) then f(x)=? -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

@Filokak: it's not f(-x) = f(x)

it's actually, f(g(-x)) = f(g(x)). So, you can't say, it's an even function.

Both are different things. Here, Sin and Cos can be treated as a different funtion.

 

Ok, try this way:

put x=x+pi

f(-Sinx) = f(-Cosx).

Also, we have, f(-Sinx) = f(Sinx) = f(Cosx)

=> f(Cosx) = f(-Cosx).

So, it can be said as constant function b'cos to satisfy the same values for Cos and Sin, there are some particular values are possible only.

 

Catalogs Discussion Forums -> Algebra -> An n digit number is a positive munber with exactly n digits.Nine hundred distinct -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

It's worth thinking a bit,

See, in n-digit number each place has 3 options only,i.e, 2,5 and 7.

so, for a 3 digit number u'll have how much possible numbers: 3*3*3 = 3^3

for an n-digit number, we'll have 3^n numbers possible.

so, all what we need is : 3^n >= 900.

i hope now you can easily find n. :)

Catalogs Discussion Forums -> Differential Calculus -> if f(sinx)=f(cosx) then f(x)=? -> Go to message
This Post 2 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]

put x= -x,

f(sin(-x)) = f(cos(-x)).

so, f(-Sinx)) = f(cosx)

we get, f(-Sinx)) = f(Sinx)

It implies, it can be true only when f(x) is constant, beacuse it's giving f(-1/2) =f(1/2) and f(-1) =f(1)

and so on...

Possible for constant function only. => f(x) =c.

Catalogs Discussion Forums -> Trignometry -> find function f(x) -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

f(x) = 1- f(1/x)

f(x) = 2 f(1+2x)

 

so, putting x=1,  f(1) = 1-f(1)

=>f(1) = 1/2.

and, f(1) = 2 f(3)

=>f(3) =1/4.

putting, x=1/2.

f(1/2) = 1-f(2)  and f(1/2) = 2 f(2)

=> f(2) = 1/3.

 

hence, we can say, f(x) = 1/(1+x)

 

Catalogs Discussion Forums -> Differential Calculus -> The answer for this according to the book is 0. Please post solution. -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

please read the last post first.
I have told that graph of cosx approaches 1 for both +0 and -0.
But it's greatest integer is always 0.
Because it's never exactly 1.
That's what i have written.
Hope it's clear now. :)

Catalogs Discussion Forums -> Differential Calculus -> The answer for this according to the book is 0. Please post solution. -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

please read the last post first.
I have told that graph of cosx approaches 1 for both +0 and -0.
But it's greatest integer is always 0.
Because it's never exactly 1.
That's what i have written.
Hope it's clear now. :)

Catalogs Discussion Forums -> Differential Calculus -> The answer for this according to the book is 0. Please post solution. -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

dude!! what i am trying to make u understand that,

cos(-x) = Cos x.

Do u remember that?

First think of it.

So, cos x where x is approaching from negative side results in cos x

see, you can see it from graph of cosx, what value it attains from +0 as well as -0.

u'll find it's just near to 1 and not 1.

clear now?

Catalogs Discussion Forums -> Differential Calculus -> The answer for this according to the book is 0. Please post solution. -> Go to message
This Post 7 points    (Olaaa!! Perrrfect answer.   in 2 votes )   [?]

look, it's easy :

first when x tends from positive side to zero.

greatest integer of cosx will result in zero =>sin0 =0 absolutely,

now for negative side,

as cos is positive in first and 4th quad.

and it's value is always less than 1,

so, it again results in zero when greatest integer is applied to it.

So, everytime your numerator is ablsolutely, Sin0, means 0.

Hence, the ans.

Hope you got it now. :)

Catalogs Discussion Forums -> Algebra -> Find values of x: (x^3-1)/x>=0 -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

it can be solved as:

((x-1)*(x^2+x+1))/x >=0

now, x^2+x+1 is always greater than 0.

so, we are just to check (x-1)/x >=0

=> x not equal to 0.

and (x-1) >=0

hance, ans is x>=1

 

Catalogs Discussion Forums -> Algebra -> whats the value of i^i.....(.i to the power of i)...? -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]

let y= i^i

logy = i log(i)

i=e^(i*pie/2)

so, logy= i*i*pie/2 loge

=> log y = -pie/2.

now, you have to just take antilog to get y.

Note: base is "e" here.

Catalogs Discussion Forums -> Algebra -> domain of 2^x+2^y=2 -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

Already told you.

I have posted the complete solution.

Refer to the post :http://www.goiit.com/posts/list/algebra-domain-of-2-x-2-y-2-1019436.htm

Catalogs Discussion Forums -> Algebra -> domain of 2^x+2^y=2 -> Go to message
This Post 10 points    (Olaaa!! Perrrfect answer.   in 2 votes )   [?]

2^y = 2 - 2^x
taking log:
ylog2 = log (2-2^x)

y = log (2-2^x)  with base 2.

Now, properties for log t  are:

1)t>0

2) base should be positive and not equal to 1. (which is 2 in our case)

 

So, 2-2^x >0

=> 2 > 2^x

=> x<1. (domain)

 

Catalogs Discussion Forums -> About IITs and JEE -> IIT - JEE mistakes of this year -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

Even profs do not agree with decisions..

There are a lots of problems coming on.

See, How they are sorting it out ..

Catalogs Discussion Forums -> About IITs and JEE -> IIT - JEE mistakes of this year -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

Do read the story :

http://timesofindia.indiatimes.com/NEWS/India/IIT-issues-clarification-on-mistakes-in-JEE-papers-/articleshow/5884640.cms

 

These are the clarification given by IIT.

Catalogs Discussion Forums -> Differential Calculus -> limit n---infinity (a^n)/n! BANSAL ASSIGNMENT QUESTION -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

Look at this problem in this way:

(a^n)/n! = (a/1)(a/2)........(a/a)......(a/k)....

these all the terms are in multiplication.

So, in denominator, it'll start from 1 and in b/w it'll be the time when denominator will be equal to a and then terms in deno starts increasing.

The number in denominator will approach to infinity.

and (a/n) where n is close to infinity is Zero.

So, the whole term multiplied by 0 becomes 0.

Hence, the ans is ZERO.

 
 
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