By "y = −9x2 − 2x" I assume you meant <span>y = −9x^2 − 2x (the "^" symbol represents exponentiation).
Let's find the first derivative of y with respect to x: dy/dx = -18x - 2. This is equivalent to the slope of the tangent line to the (parabolic) curve. Now let this derivative (slope) = 0 and solve for the critical value: -18x - 2 = 0, or
-18x = 2. Solving for x, x = -2/18, or x = -1/9.
When x = -1/9, y = -9(-1/9)^2 - 2(-1/9). This simplifies to y = -9/9 + 2/9, or
y = -7/9.
The only point at which the tangent to the curve is horiz. is (-1/9,-7/9).</span>
Answer:
2.2 hr
Step-by-step explanation:
Let t = time
95t = distance of westbound train
105t = distance of eastbound train
95t + 105t = 440
200t = 440
t = 2.2 hr.
See attachment file below.
Hope it helped!!
Answer: 72 u^2
<h3>
Explanation:</h3>
What we know:
- Both triangles are identical
- Both rectangles are different
- There are values in units^2 given
- There are right angles
How to solve:
We need to find the area of at least one of the triangles and double it. Then, we need to find the areas of both rectangles. Finally, we need to add these areas to find the total area. The final area will be represented in units squared (u^2)
<h2>
Process:</h2>
Triangles
Set up equation A = 1/2(bh)
Substitute A = 1/2(4*3)
Simplify A = 1/2(12)
Solve A = 6
Double *2
A = 12 u^2
Rectangles
Set up equation A = lh
Substitute A = (14)(3)
Simplify A = 42 u^2
Set up equation A = lh
Substitute A = [14-(4+4)](3)
Simplify A = (14-8)(3)
Simplify A = (6)(3)
Multiply A = 18 u^2
Total Area
Set up equation A = R1+R2+T
Substitute A = 42 + 18 + 12
Simplify A = 60 + 12
Solve A = 72 u^2
<h3>
Answer: 72 u^2</h3>
