trigonometric inequalities
- Thread starter mimie
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Dr.Peterson
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(a) looks good.
(b) is correct, but your work doesn't show that. Your graph is not shaded correctly for the tangent inequality you wrote. But in fact that inequality is wrong: you can't divide an inequality by a quantity that is not known to be positive, so you are going wrong from the start. Your work to find when equality holds is valid, but perhaps you should graph the original inequality rather than the tangent.
(b) is correct, but your work doesn't show that. Your graph is not shaded correctly for the tangent inequality you wrote. But in fact that inequality is wrong: you can't divide an inequality by a quantity that is not known to be positive, so you are going wrong from the start. Your work to find when equality holds is valid, but perhaps you should graph the original inequality rather than the tangent.
Dr.Peterson
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Looks good. I only suggested using the last graph you drew to determine the interval, having already solved the equality; but by writing as the cosine of a sum, you strengthened your work algebraically.