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How to quickly solve a to the nth power times a to the nth power minus 1 times a to the nth power minus 2, etc. for a = 2 and n= 3

Is this what you mean ?

$$\\a^n*a^{(n-1)}*a^{(n-2)} ...... *a^{n-n}\\\\
=2^3*2^{(3-1)}*2^{(3-2)} *2^{(3-3)}\\\\
=2^3*2^{2}*2^{1} *2^{0}\\\\
=8*4*2*1\\\\
=64$$

Thanks anon - that is a lot of sand grains :))

Hi Bio,

If you use the forum calc [Calculation e.g.1+2=3] button 

then we can all see if you have done it correctly :))

Jaheem always helps his mother look after her fruit stall. At the fruit stall, 3/7 the fruits are mangos. 3/8 of the remaining fruits are kiwis and the rest are bananas. How many fruits are there altogether if there are 130 bananas?

Let the number of fruit be F

There are (3/7)F mangoes so there are   (4/7)F that are not mangos

There are (3/8)*(4/7)F   that are kiwi fruit

the rest are bananas

so

The number of bananas = total - mangos - kiwi fruit

The number of bananas = F -  (3/7)F  - (3/8)*(4/7)F    but there are 130 bananas

so

F -  (3/7)F  - (3/8)*(4/7)F = 130

F [ 1-  (3/7)  - (3/8)*(4/7)] =130

F=130 / [ 1-  (3/7)  - (3/8)*(4/7)]

$${\frac{{\mathtt{130}}}{\left[{\mathtt{1}}{\mathtt{\,-\,}}\left({\frac{{\mathtt{3}}}{{\mathtt{7}}}}\right){\mathtt{\,-\,}}\left({\frac{{\mathtt{3}}}{{\mathtt{8}}}}\right){\mathtt{\,\times\,}}\left({\frac{{\mathtt{4}}}{{\mathtt{7}}}}\right)\right]}} = {\mathtt{364}}$$

So ther are 364 peices of fruit     

y=3x+5

d=0.000407673

400-2Y=232

400-232=2Y

168=2Y

You are 84

sec (0)=1/cos(0) = 1/1 =1

You study realy hard, have someone help you, and hope that the professor is nice.

$$\\(1.5)(10^{4}) = [0.37 - (9.8)(2.1)(10^{4})]d\\\\
(1.5)(10^{4}) \div [0.37 - (9.8)(2.1)(10^{4})]=d\\\\$$

Someone else can finish it if they want to :)

The mass of the earth is 5.98x10^24 kg and its radius is 6.38x10^6 m. Compute the density of the earth, using the power of 10 notations and the correct number of significant figures.

$$\\V=\frac{4}{3}\pi*r^3\\\\
V=\frac{4}{3}\pi*(6.38*10^6)^3\\\\
V=\frac{4}{3}\pi*6.38^3*10^{18}\\\\
Density=\frac{Mass}{Volume}\\\\
Density=\frac{5.98*10^{24}}{\frac{4}{3}\pi*6.38^3*10^{18}}\;\;Kg/m^3\\\\
Density=\frac{3*5.98*10^{6}}{4\pi*6.38^3}\;\;Kg/m^3\\\\$$

$${\frac{\left({\mathtt{3}}{\mathtt{\,\times\,}}{\mathtt{5.98}}\right)}{\left({\mathtt{4}}{\mathtt{\,\times\,}}{\mathtt{\pi}}{\mathtt{\,\times\,}}{{\mathtt{6.38}}}^{{\mathtt{3}}}\right)}} = {\mathtt{0.005\: \!497\: \!313\: \!929\: \!962\: \!6}}$$

$$Density=\frac{3*5.98*10^{6}}{4\pi*6.38^3}\;\;Kg/m^3\\\\
Density=0.0054973139299626*10^{6}\;\;Kg/m^3\\\\
Density=5.4973139299626*10^{3}\;\;Kg/m^3\\\\$$

Now volume and mass both have 3 significant figures so I think density has 3 significant figures too.

$$\\Density=5.50*10^{3}\;\;Kg/m^3\\\\$$

Here are some clips to help you understand

https://www.youtube.com/watch?v=VRtR-rv96rg

https://www.youtube.com/watch?v=__csP0NtlGI

Well aren't you clever anon :))

They are receiprocals of one another  :)

$$\\$Area of sector = (angle in degrees$/360) *pi*r^2$$

how to find the equation of a line with slope of 3 and y-intercept 5?

I think this is what you are looking for:

y = 5 + 3 x

9-9=0   that's the answer

I don't know what you mean either   

"h" is just the name of the function.  Often f is used but any letter can be used :)

And yes, you just replace the original t with -3t like the 2nd anon did. 

h(-3t) = -2(-3t) + 2

h(-3t) = 6t + 2

I'm guessing here but

the lioght will spread out in a sphere

the surface area of a sphere is   4*pi*r^2

r=5.2*10^18

So the surface are of THIS sphere is 

$$\\SA=4*\pi*(5.2*10^{18})^2\\
SA=4*\pi*5.2^2*10^{36}\\$$

$${\mathtt{4}}{\mathtt{\,\times\,}}{{\mathtt{5.2}}}^{{\mathtt{2}}}{\mathtt{\,\times\,}}{\mathtt{\pi}} = {\mathtt{339.794\: \!661\: \!412\: \!272\: \!036\: \!7}}$$

$$\\SA= 3.39797946614122720367 * 10^{38}\;\; M^2\\\\
Brightness \approx 8.9*10^{29}/(3.39797946614122720367 * 10^{38}) \;\;$watts per square metre$\\\\
Brightness \approx 8.9*10^{-9}/(3.39797946614122720367 ) \;\;$watts per square metre$\\\\
Brightness \approx 2.62*10^{-9} \;\;$watts per square metre$\\\\$$

I got the same as anon so maybe we are both correct    

a=1/b, b=1/a

485:388 and 550:440

YES THEY ARE! BECAUSE BOTH OF THEM ARE EQUAL TO 1 1/4=1.25

You know TR and DL you are both right.

Maybe you should both think about what the other is trying to tell you.

You should also try being accepting of your differences    

All types of computing knowledge is invaluable in our world, including games,  but nature also has much magnificence to offer.

If you do not sometimes feel awstruck by the magnificance of a night sky or by the antics of insect as it goes about its world, then you need to spend more time with nature learning an appreciation of all it offers :)

If this is the equation x square _9 equals to 169

YOUR QUESTION IS NOT CLEAR. STATE IT VERY CLEARLY SO WE CAN HELP YOU!.

what is 1/2 times 1,848

Doesn't mean 1848/2=924!!!!!!!!!!!!!!!!!!!!!!!!!.