Expression : tan(A + B) = X
= $$\frac{sin(A + B)}{cos(A + B)}$$
= $$\frac{sinAcosB+cosAsinB}{cosAcosB-sinAsinB}$$
Dividing both numerator and denominator by $$(cosAcosB)$$
= $$\frac{sinAcosB+cosAsinB}{cosAcosB}\div\frac{cosAcosB-sinAsinB}{cosAcosB}$$
= $$\frac{tanA+tanB}{1-tanAtanB}$$
=> Ans - (B)
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