Answer is 12.5
done by jagdish sir before by 2 method 1st limit as a sum nd other by complex number method...
Answer should be 25..
Limit is coming out to be 1/2..
@Hritik_2020 ans coming out 25
For question 73 first use property of trigo identity sinAsin2ASin3A series and then apply Ap or gp properties