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secondary 3 | A Maths
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Date Posted: 4 years ago
Views: 241
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From Calvin W.
Date Posted:
4 years ago
Should be smaller equal to 0. One repeated root means touching at one point and doesn’t go below x-axis ie never negative.
Also must note that “k” has to be positive.
If k is negative, it’s a “n” shape which will mean a part of the graph is under the x-axis ie negative.
If k is positive, itll be a “u” shape and if the “u” shape is touching or above the x-axis means that it’s fully non-negative.
This kind of question must take extra care.
Also must note that “k” has to be positive.
If k is negative, it’s a “n” shape which will mean a part of the graph is under the x-axis ie negative.
If k is positive, itll be a “u” shape and if the “u” shape is touching or above the x-axis means that it’s fully non-negative.
This kind of question must take extra care.
You are right. My mistake :)
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Very common mistake not to factor in whether k has to be positive or negative. Always look out for the coefficient of x^2 and how it has to be to fit the conditions required.
Date Posted:
4 years ago
A rule of thumb I tell my students is this
“...if you see a “k” in the coefficient of x^2 (or y^2 if the equation is in y), you must be careful)...”
In fact, we must also be careful on one other thing. We must also not allow the coefficient of x^2 to become zero, since this would make the equation a straight line graph which (in most cases) cuts the x-axis exactly once.
“...if you see a “k” in the coefficient of x^2 (or y^2 if the equation is in y), you must be careful)...”
In fact, we must also be careful on one other thing. We must also not allow the coefficient of x^2 to become zero, since this would make the equation a straight line graph which (in most cases) cuts the x-axis exactly once.
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Amended answer
Date Posted:
4 years ago
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