we have
Equate the expression to zero to find the roots
Group terms that contain the same variable, and move the constant to the opposite side of the equation
Factor the leading coefficient
Complete the square. Remember to balance the equation by adding the same constants to each side.
Rewrite as perfect squares
square roots both sides
the roots are
so
therefore
<u>the answer is the option</u>
Answer:
Step-by-step explanation:
This question is incomplete; here is the complete question.
A closed cylindrical can of fixed volume V has radius r. (a) Find the surface area, S, as a function of r. (b) What happens to the value of S approaches to infinity? (c) Sketch a graph of S against r, if V=10 cm³.
A closed cylindrical can of volume V is having radius r and height h.
a). Surface area of a cylinder is given by
S = 2(Area of the circular sides) + Lateral area of the can
S = 2πr² + 2πrh
S = 2πr(r + h)
b). Since surface area is directly proportional to radius of the can
S ∝ r
Therefore, when r approaches to infinity (r → ∞)
c). If V = 10 cm³ Then we have to graph S against r.
From the formula V = πr²h
10 = πr²h
h =
By placing the value of h in the formula of surface area,
S =
Now we can get the points to plot the graph,
r -2 -1 0 1 2
S -13.72 -13.72 0 26.28 35.13
