First multiply each term by 24(the common denominator found by 8×3) to remove the fractions and make things easier.

This will give you,

Then just continue to simplify and isolate the variable.



Answer:
Rate of change of the diameter is equal to 0.053cm/min
Step-by-step explanation:
A snowball is of the shape of a sphere
Surface area of Sphere (S)= 
Rate of change of surface area
dS/dt = -4
the negative sign indicates the surface area is decreasing.
Radius = d/2 where d represents diameter
using this is the surface area equation
S = 
= 
dS/dt = 2*pi*d*d(d)/dt
4 = 2*pi*d*(d)/dt
d(d)/dt = 2/12*pi=
cm/min
so the rate of change of the diameter is equal to 0.053cm/min
Answer:
The last choice is the one you want
Step-by-step explanation:
First of all, a parabola has a minimum value if it is a positive parabola, one that opens upward. The first and the third parabolas are negative so they open upside down. That leaves us with choices 2 and 4. We find the side to side and up or down movement by finishing the completion of the square that has already been started for us. Do this by factoring what's inside the parenthesis into a perfect square binomial.
The second one factored becomes:

which reflects a shift to the right 3 and up 1. Not what we are asked to find.
The fourth one factored becomes:

which reflects a shift to the right 3 and down 5. That's what we want!
<u>Prove that:</u>

<u>Proof: </u>
We know that, by Law of Cosines,
<u>Taking</u><u> </u><u>LHS</u>
<em>Substituting</em> the value of <em>cos A, cos B and cos C,</em>



<em>On combining the fractions,</em>

<em>Regrouping the terms,</em>



LHS = RHS proved.