Physics, Chemistry, Mathematics Forums

Dear friends please solve this 4 me whether it is too easy for you

Q-- find the equation of a circle whose radius is 5 and which touches the circle x²+y²-2x-4y-20=0 at the point (5,5).

good luck

Sir,

Is Rolle's theorem applicable to all polynomial functions?

sir,
i`m finding difficulty in integration of greatest integer function.please give me a brief method of this.

This message was originally posted by Akash Sharma

question

There are ‘n’ no. of batteries connected in series in a closed circuit such that the emf of each battery is denoted by e (i) .Each battery has its own internal resistance r(i).Given that r(i) = ke (i),such that ‘k’ is a constant.we are to find the current in the circuit if no other resistance than that of internal resistance of batteries is present. Also there is no other source of potential difference other than that through batteries.

But my question is not this

Current through the circuit is

 I= S e (i) / S r(i)

 =1/k Ãœ

accordingly a constant current is established in the circuit

But when we find the potential difference across ith battery it comes out to be

V (i)= e (i) - Ir(i)

=e (i) - I/k*k*e (i) \ givenÞ r(i)=ke (i)

=e (i) -e (i)

=0

Now the question is

HOW IS THE CURRENT FLOWING IN THE CIRCUIT IF THE POTENTIAL OF EACH BATTERY IN THE CIRCUIT IS ZERO AS THERE IS NOTHING ELSE CONNECTED IN THE CIRCUIT OTHER THAN GIVEN BATTERIES?

(FOR THIS QUESTION REFER CONCEPTS OF PHYSICS(2)H.C. VERMA PAGE NO 188 QUESTION NO. 8)

DO ANSWER THIS QUESTION

AKASH

Please help me to integrate (cos7x-cos8x)/(1+2cos5x).

i have a problem in integration

 

        cos^4A+sin^4A

$    -----------------------   dA   =  ln [1+tanA/1-tanA]   + [1/2] sinAcosA

      cos^2A - sin^2A

 i solved it in this way. can it be done in another way

cos^4A+sin^4A  =  1  -  2cos^2A sin^2A  = 1  -  [1/2] sin^2 [2A]

and cos^2A - sin^2A =  cos2A

i took sin2A as t and 2cos2A as dt and simplified

 but i couldent get the required answer

is the method correct or will i have to solve the problem in different way

sir,
one small doubt.It is given tht boron doesnt` react with acids.but it reacts with oxidising agents such sulphuric acid and nitric acid which are both acids.So my question is does boron doesn`t really react with acids???If it reacts with acids other than H2SO4 and HNO3 please send the complete reaction.thank you

sir,

i cant understand why does a time varying magnetic field induces a non conservative electric field in any loop. i mean if flux is changing, then only an emf must be induced which should obey E=-dV/dl, (ie) it should be conservative....

please help.

can anyone help me with this limit?

limit _(x->0) x^x

A particle follows SHM with its eqn.of motion being

 s(x,y)=Asinwt i + 3Asin3wt j

What is its time period? Also find the expression for total mechanical energy wrt time.