If $\tan (A-B)=\frac{1}{\sqrt{3}}$ and $\tan (A+B)=\sqrt{3}, 0^{\circ}B$ find $\mathrm{A}$ and $\mathrm{B}$.
Given:
$\tan (A-B)=\frac{1}{\sqrt{3}}$......(1)
$\tan (A+B)=\sqrt{3}$......(2)
We know that,
$\tan 30^{\circ}=\frac{1}{\sqrt{3}}$.....(3)
$\tan 60^{\circ}=\sqrt{3}$......(4)
Now by comparing equation (1) and (3)
We get,
$A-B=30$....(5)
Now by comparing equation (2) and (4)
We get,
$A+B=60 \ldots \ldots(6)$
Now to get the values of A and B, let us solve equation (5) and (6) simultaneously
Therefore by adding equation (5) and (6)
We get,
Therefore,
$2 A=90$
$\Rightarrow \quad A=\frac{90}{2}$
$\Rightarrow \quad A=45^{\circ}$
Hence $A=45^{\circ}$
Now by subtracting equation (5) from equation (6)
We get,
Therefore,
$2 B=30$
$\Rightarrow B=\frac{30}{2}$
$\Rightarrow B=15^{\circ}$
Hence $B=15^{\circ}$
Therefore the values of A and B are as follows
$A=45^{\circ}$ and $B=15^{\circ}$