Solve: Finding Positive Values for y = -1/6x² - 3⅓x
Question
Look at the following function:
y=−61x2−391x
Determine for which values of x the following is true:
f(x) > 0
Step-by-Step Solution
To solve this problem, we'll follow these steps:
Step 1: Identify the given equation in a standard form.
Step 2: Calculate the roots using the quadratic formula.
Step 3: Determine the sign of the function in different intervals determined by the roots.
Now, let's work through each step:
Step 1: The given quadratic function is y=−61x2−310x. Here, a=−61, b=−310, and c=0.
We rewrite the function as y=−61x2−310x.
Step 2: To find the roots of the quadratic equation, apply the quadratic formula: x=2a−b±b2−4ac
Plugging in the values, we get: x=2⋅(−61)−(−310)±(−310)2−4⋅(−61)⋅0
This simplifies to: x=−31310 (since the discriminant simplifies to zero as c is zero) x=0 and x=−1832 (solving for the roots)
Step 3: Determining the intervals:
Because the parabola opens downwards (as a=−61 is negative), the quadratic is positive between the roots.
Thus, f(x)>0 in the interval −1832<x<0.
Therefore, the solution to the problem is −1832<x<0.