When a line passes through the two points , its slope is given by the formula
In this question, a line L passes through the points
So, its slope is given by
When two lines are perpendicular, then the product of their slopes is -1.
Since, the slope of the line L is , so the slope of the line which is perpendicular to the given line L is
as the product of
.
(a) If <em>f(x)</em> is to be a proper density function, then its integral over the given support must evaulate to 1:
For the integral, substitute <em>u</em> = <em>x</em> ² and d<em>u</em> = 2<em>x</em> d<em>x</em>. Then as <em>x</em> → 0, <em>u</em> → 0; as <em>x</em> → ∞, <em>u</em> → ∞:
which reduces to
<em>c</em> / 2 (0 + 1) = 1 → <em>c</em> = 2
(b) Find the probability P(1 < <em>X </em>< 3) by integrating the density function over [1, 3] (I'll omit the steps because it's the same process as in (a)):