Solve y=x²+2x+2: Finding Where Function Values Are Positive

Question

Look at the function below:

y=x2+2x+2 y=x^2+2x+2

Determine for which values of x x the following is true:

f\left(x\right)>0

Step-by-Step Solution

To find for which values of x x the function y=x2+2x+2 y = x^2 + 2x + 2 is positive, we'll begin by analyzing the quadratic expression.

First, let's complete the square for the quadratic function:

y=x2+2x+2 y = x^2 + 2x + 2

To complete the square, take the coefficient of the x x term (which is 2), divide it by 2 to get 1, and then square it to obtain 1. Add and subtract this value inside the expression:

y=(x2+2x+1)+21 y = (x^2 + 2x + 1) + 2 - 1

This simplifies to:

y=(x+1)2+1 y = (x + 1)^2 + 1

Now, this function y=(x+1)2+1 y = (x+1)^2 + 1 shows a parabola in the vertex form (xh)2+k(x-h)^2 + k, where the vertex is at (1,1)(-1, 1) and opens upwards, as the coefficient of the squared term is positive.

This indicates that the minimum point, (vertex) \text{(vertex)} , is at y=1 y = 1 , which is above the x-axis. As such, the function y=(x+1)2+1 y = (x+1)^2 + 1 will be positive for all x x since the entire curve lies above the x-axis and the value of y y is always greater than zero.

Therefore, the function y=x2+2x+2 y = x^2 + 2x + 2 is positive for all real values of x x .

Hence, the solution is that the function is positive for all values of x x .

Answer

The function is positive for all values of x x .