Here is our profit as a function of # of posters
p(x) =-10x² + 200x - 250
Here is our price per poster, as a function of the # of posters:
pr(x) = 20 - x
Since we want to find the optimum price and # of posters, let's plug our price function into our profit function, to find the optimum x, and then use that to find the optimum price:
p(x) = -10 (20-x)² + 200 (20 - x) - 250
p(x) = -10 (400 -40x + x²) + 4000 - 200x - 250
Take a look at our profit function. It is a normal trinomial square, with a negative sign on the squared term. This means the curve is a downward facing parabola, so our profit maximum will be the top of the curve.
By taking the derivative, we can find where p'(x) = 0 (where the slope of p(x) equals 0), to see where the top of profit function is.
p(x) = -4000 +400x -10x² + 4000 -200x -250
p'(x) = 400 - 20x -200
0 = 200 - 20x
20x = 200
x = 10
p'(x) = 0 at x=10. This is the peak of our profit function. To find the price per poster, plug x=10 into our price function:
price = 20 - x
price = 10
Now plug x=10 into our original profit function in order to find our maximum profit:
<span>p(x)= -10x^2 +200x -250
p(x) = -10 (10)</span>² +200 (10) - 250
<span>p(x) = -1000 + 2000 - 250
p(x) = 750
Correct answer is C)</span>
Let's solve your inequality step-by-step.<span><span><span>−1</span>+<span>4y</span></span><31</span>Step 1: Simplify both sides of the inequality.<span><span><span>4y</span>−1</span><31</span>Step 2: Add 1 to both sides.<span><span><span><span>4y</span>−1</span>+1</span><<span>31+1</span></span><span><span>4y</span><32</span>Step 3: Divide both sides by 4.<span><span><span>4y</span>4</span><<span>324</span></span><span>y<<span>8</span></span>
<span>Simple. The Law of Reflection states that the angle of incidence is equal to the angle of reflection. These two angles are measured relative the normal line (line perpendicular to the surface). The angle of reflection is therefore 34 degrees also. However, since the question is asking for the angle relative to the mirror, then the answer is 90-54 = 36</span>° Thus your answer is C. 36°
