Melody

The sum of the first term is 120?

I think that there is a number missing here!

I'll let you know Chris.

A cone is a circular pyramid.

The volume of any pyramid is $$\frac{1}{3}$$ x area of base x perpendicular height

now the base is a circle and the area of a circle is $$\pi r^2$$

so

$$V=\frac{1}{3}\: \pi r^2h\quad units^3$$

Fri 16/5/14

Difficult one

you divide 800 by 117 and then take the whole number part.

Thank you Heureka

$$\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{cos}}{\left({\mathtt{x}}\right)} = \underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{cos}}{\left({\mathtt{180}}{\mathtt{\,-\,}}\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{cos}}^{\!\!\mathtt{-1}}{\left({\frac{{\mathtt{0.25}}{\mathtt{\,\times\,}}\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{cos}}{\left({\mathtt{x}}\right)}}{{\mathtt{6.76}}}}\right)}\right)} \Rightarrow \underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{2\pi}}}{{cos}}{\left({\frac{{\mathtt{\pi}}{\mathtt{\,\times\,}}{\mathtt{x}}}{{\mathtt{180}}}}\right)} = {\mathtt{\,-\,}}{\frac{{\mathtt{25}}{\mathtt{\,\times\,}}\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{2\pi}}}{{cos}}{\left({\frac{{\mathtt{\pi}}{\mathtt{\,\times\,}}{\mathtt{x}}}{{\mathtt{180}}}}\right)}}{{\mathtt{676}}}}$$

Umm that doesn't look very helpful.

Okay lets try something else

Thank you, that was a much nicer way to ask.  

$$x-15=2x+11\\
-15=x+11\\
-15-11=x\\
-26=x\\
x=-26$$

Hi Heureka,

I pasted your code (in the above post) into Texmaker at home and it will not run.  I want to play with it.  I thought it may need the $ signs around it but that didn't help.  Have you got any ideas on how i can get it to run.  I am not very good at deciphering the error messages.  I can past in the errors if it would help.

any ideas?

Thank you.