Melody

Do you want

$$-8/9^3=-8/729\\
or\\
-(8/9)^3=-(8^3/9^3)=-512/729\\
or\\
(-8/9)^3=(-8)^3/9^3=-512/729$$

Okay rosala,

I have improved the layout.  Now let's see if we can work through it.  

I invite comment on this one.  

Let me see...

15 applicants.    5 sportA,     5 sportB    and     5 sportC

9 will be recruited and not more than 4 from any individual sport

possibilities

441      414      144        I think the number here is  5C4*5C4*5C1 = 3* 5*5*5 = 3*125 = 375

432   423  342   324   234   243   I think the number here is  6*5C4*5C3*5C2 = 6*5*10*10=6*500=3000

333    I think the number here is   1* (5C3)^3  =10^3 = 1000

So there seems to be 10 ways that the numbers from each sport can be chosen.

I think there are  375+3000+1000=4375 different ways that the 9 can  be selected.      

Chang all the units to m before you start.

Actually, it is not so straight forward because I am not sure which two equal sides you are meant to omit, probably the 2 smallest one  

They are just 4 rectangles.  Find the areas and add them up.  

Have a go and if you get stuck post with what you have tried.  

You will find the formula here

Here is the formulary page theat will help you.

It is right here on the web2 site!   

This is very similar to you last question.  only easier.  

You have a go at it by yourself.

. תודה לך -. אני שמח שאתה אוהב את זה

6 sin x − 3 sin 2x=12/π

You can solve this graphically in differnent ways.

The 2 online graphing calculators that I will recommend are Desmos and Wolfram|Alpha.

you can also do some graphing on the web2 calc.

Cos of an angle must be between -1 and 1 so this question makes no sense!