Calculate Area Under y=-(x-3)²: Negative Quadratic Function

Question

Find the positive area of the function

y=(x3)2 y=-(x-3)^2

Video Solution

Solution Steps

00:00 Find the positive domain of the function
00:03 Use the abbreviated multiplication formulas and expand the parentheses
00:12 Negative times positive is always negative
00:15 Negative times negative is always positive
00:22 Let's look at the coefficient of X squared, it's negative
00:25 When the coefficient is negative, the function is concave down
00:30 Now we want to find the intersection points with the X-axis
00:34 At the intersection point with X-axis, Y=0, let's substitute and solve
00:40 Change from negative to positive
00:43 Take the square root to eliminate the exponent
00:47 Isolate X
00:50 This is the X value at the intersection point with the X-axis
00:56 Let's draw the function according to the intersection points and function type
01:02 The function is positive while it's above the X-axis
01:07 The function is always below the axis, therefore it's never positive
01:11 And this is the solution to the question

Step-by-Step Solution

To determine the positive area of the function y=(x3)2 y = -(x-3)^2 , we start by examining the properties of the given function:

  • The function y=(x3)2 y = -(x-3)^2 is a quadratic in the form y=a(xp)2 y = -a(x-p)^2 where a=1 a = 1 and p=3 p = 3 .
  • This represents a downward opening parabola with a vertex at (3,0) (3, 0) .

The function is defined as the negative of a square, so y y will always be less than or equal to zero. In equation form, (x3)20 -(x-3)^2 \leq 0 . We solve for the conditions under which this function could be positive:

  • For the expression (x3)2-(x-3)^2 to be greater than zero, (x3)2>0-(x-3)^2 > 0, is impossible because the squared term (x3)2(x-3)^2 is always non-negative and its negative is thus always non-positive.
  • At the vertex x=3 x = 3 , (x3)2=0 -(x-3)^2 = 0 , the function is exactly zero.

This analysis reveals that the function does not achieve positive values in any part of its domain.

Therefore, there is no positive area for the function y=(x3)2 y = -(x-3)^2 .

Answer

There is no positive area.