Answer:
52.16
Step-by-step explanation:
So, Lets find out the discount first. Since the shoes are 30% off, that means the shoes are 70% of their original price, so lets multiply the original price of 69 by .7. 69*.7=48.3
Now to find the sales tax we need to multiply the price we got finding the sale by 1.08 since the sales tax is added on not removed from the price. 48.3*1.08=52.16
The prices after the sale and including tax is 52.16
Diagram B because the points are all over the place.
I have a solution here that has a slight change in given where instead of <span>(4, 32), it is (3, 18). However, since the solution has provided explanations on each process, step-by-step, I believe that by thoroughly analyzing it, you might just answer this problem on your own!
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f(x) = 2x² ← this is the parabola
f(3) = 2 * 9 = 18 → the parabola passes through A (3 ; 18), so its tangent line too
f'(x) = 4x ← this is the derivative
…and the derivative is the slope of the tangent line to the curve at x
f'(3) = 4 * 3 = 12 ← this is the slope of the tangent line to the curve at x = 3
Equation of the tangent line
The typical equation of a line is: y = mx + b → where m: slope and where b: y-intercept
You know that the slope of the tangent line is 12.
The equation of the tangent line becomes: y = 12x + b
The tangent line passes through A (3 ; 18), so these coordinates must verify the equation of the tangent line.
y = 12x + b
b = y - 12x → you substitute x and y by the coordinates of the point A (3 ; 18)
b = 18 - 36 = - 18
→ The equation of the tangent line is: y = 12x - 18
Intersection between the tangent line to the curve and the x-axis: → when y = 0
y = 12x - 18 → when y = 0
12x - 18 = 0
12x = 18
x = 3/2
→ Point B (3/2 ; 0)
Intersection between the vertical line passes through the point A and the x-axis: → when x = 3
→ Point C (3 ; 0)
The equation of the vertical line is: x = 3
Area of the region bounded by the parabola y = 2x², the tangent line to this parabola at (3 ; 18), and the x-axis.
= (area of the region bounded by the parabola y = 2x² and the x-axis) - (area of the triangle ABC)
= [∫ (from 0 to 3) of the parabola] - [(xC - xB).(yA - yC)/2]
= [∫ (from 0 to 3) 2x².dx] - [(xC - xB).(yA - yC)/2]
= { [(2/3).x³] from 0 to 3 } - { [3 - (3/2)].(18 - 0)/2 }
= [(2/3) * 3³] - { [(6/2) - (3/2)] * 9 }
= [(2/3) * 27] - { [(3/2) * 9 }
= 18 - (27/2)
= (36/2) - (27/2)
= 9/2 square unit
