- #1
SciencyBoi
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Homework Statement
Find the solution of the inequality ## \sqrt{5-2sin(x)}\geq6sin(x)-1 ##
Answer: ## [\frac{\pi(12n-7)}{6} ,\frac{\pi(12n+1)}{6}]~~; n \in Z##
Homework Equations
None.
The Attempt at a Solution
There are two cases possible;
Case-1: ##6sin(x)-1\geq0##
or ##~~~~~~~~\sin(x)\geq\frac{1}{6}##
Here, we can square both sides to get the following;
##18\sin(x)-5\sin(x)-2\leq 0##
##(9\sin(x)+2)(2\sin(x)-1 \leq 0##
## \frac{-2}{9} \leq \sin(x) \leq \frac{1}{ 2}##
Case-2:##6sin(x)-1\leq0##
or ##~~~~~~~~\sin(x)\leq\frac{1}{6}##
This interval has to be discarded from the interval that is obtained from case 1.
And we have to consider the conditions obtained above, which I'm not able to I as##~ \arcsin(\frac{-2}{9})## is a little overwhelming and also, doesn't correspond to the answer given. Please guide further.
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