We have
sin(α+β)=1
⇒sin(α−β)=sinπ2
⇒α+β=π2 .....(i)
and, sinα−β=12
⇒sin(α−β)=sinπ6
⇒α−β=π6 ....(ii)
Adding equations (i) and (ii), we get
2α=π2+π6=4π6=2π3
⇒α=π3
Putting α=π3 in equation (i), we get
π3+β=π2
⇒β=π2−π3
⇒β=3π−2π6=π6
⇒β=π6
Now, tan(α+2β)=tan(π3+2×π6)
=tan(π3+π3)
=tan2π3
=tan(π2+π6)
=−cotπ6
=−√3
∴tan(α+2√3)=−√3
and, tan(2α+β)=tan(2×π3+π6)
=tan(2π3+π6)
=tan(4π+π6)
=tan(5π6)
=(π2+π3)
=−cotπ3
=−1√3
∴tan(2α+β)=−1√3