Melody

sin(x) = 0,8 x = ?

x= inverse sin (0.8 )

x= sin^-1(0.8)

x=arc sin(0.8)

x=asin(0.8)

these are different ways of writing the same thing

put 

asin(0.8) into the web2.0calc and you will get your answer :))

$$\\9e^2 \times (-4ce)=-36ce^3\\\\$$

I do not understand this question.

Maybe someone else will.

Did you leave anythng out?

Now that would depend on what the question is   

Heureka 3/8/15

Bredth =B

length = 3B

perimeter = 3B+B+3B+B = 8B  units

Area = $$3B*B = 3B^2$$     units^2

Perhaps you mean:

$$\\\frac{(6-2ab-18^2b^3)}{12}\times a^4b\\\\
=\frac{(3-ab-9^2b^3)}{6}\times a^4b\\\\
=\frac{a^4b(3-ab-81b^3)}{6}\\\\$$

Now, if you want to, you could expand the brackets.

You are very welcome :)

Good work RT       (aka TR)

The formula for a circle is $$(x-h)^2+(y-k)^2=r^2$$

Where (h,k) is the centre of the circle and r is the radius