AM-2707

Double angle formulae

A Math · Secondary 4 · Hard · Double angle formulae

Solve, for

0^\circ\le x\le180^\circ

, the equation

3\sin2x-4\cos x=0

.

$x=41.8^\circ,90^\circ,138.2^\circ$
$x=48.2^\circ,90^\circ,131.8^\circ$
$x=30^\circ,90^\circ,150^\circ$
$x=41.8^\circ,138.2^\circ$

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