The answer is 2^5r^5
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Multiply 7 x 12 which is 84, 8x2 is 16, 16 divded by 3 is 5, so 5 minutes
That's all I remember rn. Graphing site is desmos.com if you wanted to know.
The answer to your problem is x= 15/8 as decimal form it’s 1.875
One thing to bear in mind with trigonometric expressions is that, the exponent location is next to the function name, instead of the whole expression, though it applies to the whole thing, namely cos²(x), is really [ cos(x) ]², and that matters for using the chain rule.