Which is the best estimate for the width of your index finger
2 answers:
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To be a function, it has to pass the vertical line test, which means a vertical line drawn anywhere in the graph should cut the graph only once, not more.
To be a one-to-one function, it has to pass the vertical line test as well as the horizontal line test, which means that a horizontal line drawn anywhere in the graph should cut the graph only once, not more.
<em>Of course, it passes the vertical line test, so its a function. </em>
<em>Does it pass the horizontal line test? </em><em>NO! </em><em>As shown in the attached picture, the blue line (horizontal line) cuts the graph at 3 places. We therefore eliminate choices A and B. We can eliminate choice C because nowhere is it required a function to pass through the origin for it to be one-to-one. Hence, the answer is D (blue line shows this).</em>
<em>ANSWER: D</em>
Answer: Choice A
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Explanation:
One shaded region is below the parabola, and the other shaded region is below the line. They both overlap outside the parabola, but under the straight line.
Since both shaded regions are below their respective boundaries, this means that we'll be using "less than" signs for each inequality. The solid boundary lines indicate "or equal to" is part of that as well.
Because of this, the answer is between A and D since both involve inequality signs that have "less than or equal to".
However, we can rule out choice D since the inequality would have the boundary line
, and this boundary line has a positive slope. But notice how the red diagonal line slopes downward as we read from left to right. Therefore, the red line must have a negative slope. Luckily, choice A has one of the boundary lines as y = -x+3 to fit the description. So that's why choice A is the answer.