Question:
If $3 \cot \theta=2$, show that $\left(\frac{4 \sin \theta-3 \cos \theta}{2 \sin \theta+6 \cos \theta}\right)=\frac{1}{3}$.
Solution:
It is given that $\cot \theta=\frac{2}{3}$.
$\mathrm{LHS}=\frac{4 \sin \theta-3 \cos \theta}{2 \sin \theta+6 \cos \theta}$
Dividing the above expression by $\sin \theta$, we get:
$\frac{4-3 \cot \theta}{2+6 \cot \theta} \quad\left[\because \cot \theta=\frac{\cos \theta}{\sin \theta}\right]$
Now, substituting the values of cot
$\frac{4-3\left(\frac{2}{3}\right)}{2+6\left(\frac{2}{3}\right)}$
$=\frac{4-2}{2+4}=\frac{2}{6}=\frac{1}{3}$
i.e., LHS = RHS
Hence proved.