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Please help!
maths trig functions

Please help! maths trig functions-example-1
User Shabbychef
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1 Answer

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1. According to the plot, this happens twice for some
x between 135° and 180°, and for some
x between 270° and 315°.

We could try finding them exactly, but we would end up having to solve a 4th degree polynomial equation that doesn't factorize nicely...

2. Rewrite the inequality as


3\sin(x) - 2 > \tan(x) \implies 3 \sin(x) > \tan(x) + 2

The curve
y=3\sin(x) lies above
y=\tan(x)+2 when
90^\circ < x < \alpha, where
\alpha is the first solution mentioned in (1) between 135° and 180°, approximately
\alpha\approx151.127^\circ.

3. Rewriting


\tan(x) \ge 1 \implies \tan(x) + 2 \ge 3

we see from the plot that this is true for
x between 45° and 90°, and again between 225° and 270°.

User Carey
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