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#2 Re: Help Me ! » Successive differentiation » 2016-06-17 10:45:53

Thank you so much for the help thickhead,it solved my problem ,but one thing u said, I cant figure it out is that if

is expressed in terms of
, I guess in this problem its not possible for x = 0.


#3 Re: Help Me ! » Successive differentiation » 2016-06-15 02:29:11

I also found that,I differentiate  the function upto third order and that's what the logic look likes.
But again I didnt understood the last three steps so I didn't change it . It is what written in my book.

#4 Help Me ! » Successive differentiation » 2016-06-14 22:58:43

Replies: 6

Find the value of


In the my book  its already solved the problem is that I don't understand after a certain point ,the steps.
After solving we have

Putting x = 0

Replacing n by n-2,we get similarly

After this point /step I don't understand anymore ,here is the rest which I want you people to explain me how and why its done (which is actually my question) ...


(the first and second derivative at 0 )


,if n is even


,if n is odd


#5 Re: Help Me ! » Square of any determinant is symmetric. » 2016-05-26 10:40:07

Well I too agree,but the problem is its not only in one book but rather more than one author is describing something like this.In that post I already gave some links to the books.

#6 Re: Help Me ! » Square of any determinant is symmetric. » 2016-05-26 08:12:48

I asked this question on other fourms but I didnt got any answer
Here is a link please read it … ic.873144/
FluxBB bbcode test

#7 Help Me ! » Square of any determinant is symmetric. » 2016-05-25 04:11:56

Replies: 5

This property is given in my book.
The square of any determinant is a symmetric determinant.
Well it works when I take a determinant say 3x3 and multiply it by itself using row to row multiplication.
But it fails if I multiply using row to column.


#9 Re: Help Me ! » Square Root of a square of a cross product » 2015-12-10 20:36:18

OK I got that (It should be the case), but I want to know if that is a vector rule? if yes can you give me a resource where I can understand why its like that and more.

zetafunc Thanks

#10 Help Me ! » Square Root of a square of a cross product » 2015-12-10 08:26:00

Replies: 4

Hi I got a problem

Let a and b be two vectors...
(a x b) = |a| |b| sin(t) n

where  t is the angle between the two vectors a and b ,and  n is the unit vector in the direction as per right hand rule.

If I square the equation
(a x b)^2 = |a|^2 |b|^2 (sin(t))^2 n^2

(a x b)^2 = |a|^2 |b|^2 (sin(t))^2

Now if I take the square root of both the sides

(a x b) = |a| |b| sin(t)  ...which is the problem LHS is vector and RHS is scaler

I think there is some rules for vectors which I didn't follow may be... but what please explain and give me some reference where I can read more about this.


#12 Help Me ! » Integration problem » 2014-10-09 06:43:57

Replies: 2

Well I solved this in two ways ,one of them is wrong or what I dont know

First answer is

Which is correct as many book have them
But if I try to put  1 = tan(pi/4) and then try to solve it I get something else

I am not able to understand it ,can anybody explain me where I am wrong.....


#13 Re: Help Me ! » Radius of a circular section of a sphere » 2014-01-23 03:50:03

Well I did it like this
By equation of the sphere its already given that the sphere is at origin (0,0,0).
Now from there we get radius of the sphere is

Now we have to find the distance 'd' of the plane
from origin
and that will be

Now use Pythagoras theorem to find the radius of the section by the plane

Good Luck smile

#15 Help Me ! » Radius of a circular section of a sphere » 2014-01-20 19:33:56

Replies: 7

Find the radius of the circular section of sphere

by the plane

My answer came out to

Did I did it correctly,I am bit confused over the question.


#16 Re: Help Me ! » Trigonometric equation problem... » 2013-07-23 01:33:50

Hi bob

When I  solve the equation

my answer is

And when I solve the equation

my answer is

Now which one is correct ,are both correct?

Now putting the different values for "n" we can get the value for theta and put it in the equation and check,but I did just a couple and I know if I can graph it it will show but which application to use for this kind of job I dont know.


#17 Help Me ! » Trigonometric equation problem... » 2013-07-22 23:20:43

Replies: 3


I know that

1) The general solution for



2) The general solution for



Now my question is, in an equation like

,which way should I select i.e.. its in both the forms


in that case we rewrite the equation

Thanks smile

#18 Re: Help Me ! » Physic math problem » 2013-06-11 19:53:59

Yes stefy I agree with you,  but still we use approx symbol for that... don't we ?,in the book they directly used equal symbol.

Bob the topic was about... calculating vectors...
Their are two force vectors given,first one 70N north and another is 50N south west,so calculate the resulting force and direction.

#19 Re: Help Me ! » Physic math problem » 2013-06-11 05:02:17

Well,I thought that but in that case physics books use

approx symbol in general.

So I am right with the math ?

#20 Help Me ! » Physic math problem » 2013-06-11 03:59:09

Replies: 6

In a physic book I found this

Is the math correct ? as far my math goes it should be 1.02

Thanks smile

#21 Re: Help Me ! » Trigonometry Problem » 2013-06-07 05:32:38

Yes dude it make sense now ,I tried to solve and after coming to this point I gave up

Thanks anonimnystefy and Bob for the help...

#22 Re: Help Me ! » Trigonometry Problem » 2013-06-07 02:57:36

And thanks Bob and anonimnystefy for the reply

#23 Re: Help Me ! » Trigonometry Problem » 2013-06-07 02:55:33

Sorry for late reply...
Here is how I did

The answer in the book is sin(a + b) = 24/25 as bob got 0.96,@Bob but I didn't understood what you did... can you explain and why my equation is not working

#24 Help Me ! » Trigonometry Problem » 2013-06-06 20:22:48

Replies: 11

Hi, guys

I tried but I can't  solve it...

If a,b are two different values of x lying between 0 and 2 pi (i.e.. 0 to 360 degrees) which satisfy the equation 6 cos x + 8 sin x = 9 ,find the value of sin(a + b).

Well what I did was I turned that equation into an quadratic equation and find the roots and also use the relation of the sum of the roots.But no luck my solution is getting no where....

here is what I got when I turned it into an quadratic...


#25 Re: Dark Discussions at Cafe Infinity » Which Graphic Card and Laptop » 2013-05-21 03:39:36

I will  purchase a laptop (Dell Inspiron 14R) with it installed.The over all cost seems ok.

Nvidia GeForce GT 730 M is designed for laptops/notebooks,for desktop their are other series both from AMD and Nvidia like Nvidia GTX series is best on desktop platform ,for future I am planning to buy a graphic card from GTX series for my desktop.

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