Problemas
lim x arrow (5 pi)/(6)(cos 2 x-csc 3 x)
Roztwór
Alessandra
élite · Tutor durante 8 años
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(262 Votos)
Respuesta
To evaluate the limit \(\lim_{x \rightarrow \frac{5\pi}{6}} (\cos 2x - \csc 3x)\), we first need to understand the behavior of each trigonometric function as
approaches
.1. **Evaluate
:** As
, we have:
The cosine of
is equivalent to the cosine of
(since
), which is:
2. **Evaluate
:** As
, we have:
The cosecant function,
, is the reciprocal of the sine function. At
, the sine function is:
Therefore, \(\csc\left(\frac{5\pi}{2}\right) = \frac{1}{\sin\left(\frac{5\pi}{2}\right)} = 1\).Now, substituting these values into the original expression, we get:
Thus, the limit is
.