Math Is Fun Forum

I still dont understand what you did or divided to get 4x².  If x = 0 then 4x³ / 0 cannot be done? this is the stage at where im getting confused.  you said that with the constraint dividing by x is allowed, but what value did you use x as to divide by?

I think i get it now did you divide everything by 4x?
as in (4x³/4x) + (8xy²/4x) - (4x/4x) = x² + 2y² - 1 ??

Thank you very much for the reply.  I am a bit confused at the above, firstly i thought it would have been 4x³+ (8y² - 4) = 0 but you have 4x². 

Also im guessing you solved 4x³+ (8y² - 4) = 0 by dividing everything by 4? ( which i have to substitute back in later to find the nature of the stationary points?) 

Sorry if i seem a but dumb but maths is not my strongest subject heh..

Hi again...Ok I have some more questions for you!!!!!! These are mixed diffrentiation and intergration and are pretty hard........ i will state whther to diffrentiate or intergrate..

Diffrentiate the following with respect to x:

(a)y=5x+1

(b)f(x)=6x² -ln2x

(c)y=2(x+cos2PIEx)³

(d)f(x)=x^4e^-³x

(e)y=sin²x/2x+3

Evaluate the following integrals:

(a) ∫(2x+1/x+2)dx

(b)^4∫^°(1+2/ √t)dt
{the small zero is at the bottom of the curvy line}

(c) ^PIE/4∫^°4sin2θdθ
{the small zero is at the bottom of the curvy line}

(d) ∫x(x-3)^4dx       Use the substitution u=x-3

HAHAH lets see how quick and accurate you can respond to these questions!!!!!!