Given the inequality: x2−29x<0 To solve this inequality, we must first solve the corresponding equation: x2−29x=0 Solve: This equation is of the form
a*x^2 + b*x + c = 0
A quadratic equation can be solved using the discriminant. The roots of the quadratic equation: x1=2aD−b x2=2a−D−b where D = b^2 - 4*a*c - it is the discriminant. Because a=1 b=−29 c=0 , then
D = b^2 - 4 * a * c =
(-29)^2 - 4 * (1) * (0) = 841
Because D > 0, then the equation has two roots.
x1 = (-b + sqrt(D)) / (2*a)
x2 = (-b - sqrt(D)) / (2*a)
or x1=29 x2=0 x1=29 x2=0 x1=29 x2=0 This roots x2=0 x1=29 is the points with change the sign of the inequality expression. First define with the sign to the leftmost point: x0<x2 For example, let's take the point x0=x2−101 = −101 = −101 substitute to the expression x2−29x<0 (−101)2−10(−1)29<0
291
--- < 0
100
but
291
--- > 0
100
Then x<0 no execute one of the solutions of our inequality is: x>0∧x<29