Melody

That is a very good question anon.  

A dollar times by 0 can be interpreted  as zero lots of a dollar which is certainly nothing (no money anyway)

Now by the same logic 0 times 0 could be said to be zero lots of nothing  which means that you cannot have nothing because I just said I have zero lots of nothing.

 logically this should/could mean that you have something. Because if you don't have nothing then you must have something.

0*0=0  this is what I have always believed to be true but after this logical examination of the situation perhaps another mathematician would like to comment.   

Press (scientific) in the top right corner of the calc

There is a drop down menu - vectors/matrices is one of the choices

when in there - there is a button on the left where you can choose vectors or matrices 

then it is pretty obvious I think   

Thanks anon.

You could do it this way too

$$\\\frac{2}{5}(1a-15)\le4\\\\
\frac{2}{5}\times\frac{5}{2}\times(1a-15)\le4\times\frac{5}{2}\\\\
(1a-15)\le 10\\\\
a-15\le 10\\\\
a-15+15\le 10+15\\\\
a\le 25\\\\$$

Is that an answer you got on your calc?

It   means           $${\mathtt{8.33}}{\mathtt{\,\times\,}}{{\mathtt{10}}}^{\left(-{\mathtt{5}}\right)}$$   =   0.0000833

Please note that arc cos [acos] is trhe same as inverse cos     

$$\frac{125}{1000}=\frac{1}{8}$$

What does iqual mean?  plus you need to use brackets

Is this what you mean ?

(3x)/(x-5 )=( 1+15)/(x-5)

$$\frac{3x}{x-5} =\frac{1+15}{x-5}$$

Just about anything.

New and old depend on your perspective :)

Thank you Saseflower  

I am sorry saseflower but I have whited out your answer.

This person can use the site calc just as good as you can.

And this type of rudeness (and laziness) is not to be rewarded.

I hope that you understand.  

I like that you have been so active on the forum.  You are a great asset to us.