In a triangle $ABC$, $AB=3$ cm and $AC=2$ cm. If angle $BAC$ is increasing at a constant rate of $0.

Question

In a triangle $ABC$, $AB=3$ cm and $AC=2$ cm. If angle $BAC$ is increasing at a constant rate of $0.1$ radians per second, find the rate of increase of the length $BC$ at the instant where $BAC=\frac{\pi }{3}$ radians.

Accepted Answer

$\frac{3\sqrt3}{10\sqrt7}\text{ cm/s}\approx0.196\text{ cm/s}$

2009 NJC P1 Q7

2009 NJC P1 Q7

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