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Calculus Level 4

Find the number of solutions to the equation below.

4 x 3 x + 8 x 2 = 13 + 2 cos x 4\lfloor x^3-x \rfloor + 8\lfloor x^2 \rfloor = 13 + 2\lfloor \cos x \rfloor

Notation : \lfloor \cdot \rfloor denotes the floor function .


The answer is 0.

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1 solution

Pulkit Gupta
Feb 26, 2016

This is a non rigorous solution and I do not recommend it using it for similar/related questions.

Note that RHL, 13 + 2 cos ( x ) \large 13 + 2 \cos(x) can attain values 11 , 13 , 15 \large 11,13,15 . All odds.

The LHL is the sum of two even terms, each multiplied by an integer. Since, an even number multiplied by any integer gives an even integral value, it can never return odd terms.

Hence, we infer zero solutions.

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