Remember that the area of a rectangle is the length of the rectangle multiplied by the width of the rectangle.
In this case, we could say (where 
is the area of the rectangle):
Substituting the values the problem gave us for 
and 
, we can find the formula for 
in terms of 
, which is:
The formula for the area of the rectangle would be A(x) = 10x³ - 20x² + 65x.
Answer:
r = -5
Step-by-step explanation:
common ratio (r) is found be dividing one term by its preceding term:
r = 275 ÷ -55 = -5
or, r = -55 ÷ 11 = -5
Therefore, r = -5
Can you attach a pic of the shape please?
I'll explain how to do the first one:-
y = cos-1(x2)
This can be described as ' a function of a function' x^2 is a function of x and cos-1(x^2) is a function of x^2.
We need to apply the chain rule.
Personally I find this easier to understand if i let u = x^2, so
If y = f(u) and u is a function of x then
dy/dx = dy/ du * du/dx
Here u = x^2 and y = cos-1(u)
du/dx = 2x
so dy/dx = d(cos-1(x^2) dx = dy/du * du/dx
= -1 / √(1 - u^2) * 2x
= -2x / √(1 - u^2)
= -2x / √(1 - (x^2)^2)
= -2x / √(1 - x^4)
I hope this helps. but if not. you might like to employ the formulae in the question - The square boxes contain the 'u' s in my answer. These formulae are equivalent to my explanation.
