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PLEASE HELP THIS IS TRIGONOMETRY!!!

PLEASE HELP THIS IS TRIGONOMETRY!!!-example-1
User Tsvetan Ovedenski
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\text{Given that, }\\\\~~~~~~~~~\sin \theta = \frac 35\\\\\implies \sin^2 \theta = \frac 9{25}\\\\\implies 2\sin^2 \theta = 2 *(9)/(25)\\\\\implies 1-\cos 2\theta = (18)/(25)\\\\\implies \cos 2\theta = 1-(18)/(25)\\\\\implies \cos 2 \theta = \frac 7{25}