There's no diagram here so I can't be specific, but I've attached an image.
We have the triangle 30° - 60° - 90°.
The lenght of the sides are in proportion: 
Linear functions parabola mostly things in algebra
<h3>Answers:</h3>
- (a) The function is increasing on the interval (0, infinity)
- (b) The function is decreasing on the interval (-infinity, 0)
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Explanation:
You should find that the derivative is entirely negative whenever x < 0. This suggests that the function f(x) is decreasing on this interval. So that takes care of part (b).
The interval x < 0 is the same as -infinity < x < 0 which then translates to the interval notation (-infinity, 0)
Similarly, you should find that the derivative is positive when x > 0. So the function is increasing on the interval (0, infinity)
