Recent content by Cheman

My question has always been why is the tangent function called thwe tangent function? :biggrin:

The independence of horizontal and vertical motion... Obviously it is possible to prove the independence of horizontal and vertical motion empirically - we only need look at projectile motion following a parabolic path. However, I have never found a convincing algebraic proof the for the...

Hypothesis testing with normal distribution... I've been learning about Hypothesis testing with normal distribution, but I don't understand the need for the significance level. By this I mean that i understand that according to the Central Limit Theorem a distribution of the means will be a...

Why do muscle fibres need T-tubules for the action potential to go down to stimulate the sarcoplasmic reticulum to release calcium ions? Why couldn't it just travel along the sarcomere? Thanks. :-)

Square root of 2... Is it actually possible to produce a right angled triangle with sides exactly equal to 1m and 1m? Because this would produce a hypotenuse with length "square root of 2" m, which has no exact length. Thanks in advance. :smile:

Square root of -1... We say that the square root of -1 is equal to i ( or j ), and that this is therefore not a real number - but what is this fact actually useful for? Why over complecate things with something not on the number line - why is it so useful to treat the square root of -1 as a...

How many orders can we have of 3 red roses and 3 white roses arranged in a circle? Apparently the answer is 10 - but how do yiou work it out? I know that in a circle of "n" different objects the number of different arrangements is (n-1)!, but what about the repeats? If anyone could explain a...

So if the field only "breaks way" when a wave is formed, does that mean that electrical fields do not usually take the time for light to travel to cause an effect? ie - are they instantaneous?

Erm... could anybody please add some input and help? :rolleyes: Thanks in advance. :smile:

Actually, i had more in mind during valve replacement surgary - why is there gona be oxygen reduction then? And surely what i said did make sense - if all the reactions slow down then surely the reactions of cellular respiration will also slow down? Therefore, the energy source being made...

But why do you want to run in on "low-oxygen consumption"? Also, surely if you cool the heart you will slow down the rate of respiration (which is a chemical reaction and relies on thermodynamics too) so the cell will be supplying itself with less energy anyway, as well as not needing as much...

Antigen-presenting cells... When antigen-presenting cells (eg - macrophages, dendritics, etc) encounter antigens, do they all migrate to the lymph nodes? What causes them to do this? I know from sources I've read that dendrites do it, but do macrophages as well - or does the macrophage...

Cool. :smile: Why does cooling the heart slow down its metabolism? Thanks in advance.

According to sources I've read, the heart can be stopped by flooding it with "a cold solution containing potassium ions" - why must it be cold? Thanks in advance. :smile:

Phagocytosis and chemotaxis... How can phagocytes know to move towards a site of infection yet not be able to identify what the pathogen/ antigen actually is? ie - be non-specific? How does it manage to respond to it without knowing what it actually is? Thanks. :smile: