Where does the mark scheme get these numbers from?

[TheePhysicsStudent]

Homework Statement

practicing some Trigonmetric identities and equations questions, and unsure how the mark scheme managed to reach what sin theta is equal to (Q 4B)

Relevant Equations

sin^2 x + cos^2 x =1

Q4B

Mark scheme

My working

 

[TheePhysicsStudent]

NVM guys, i just realised that the quadratic formula was used! Sorry for anyone who may have wasted time

 

[WWGD]

Your factorization, 3 lines from the bottom, is incorrect
The step from[Edit]
$Sin^2(\theta)+Sin(\theta)-1=0$ , to
$Sin(\theta)[Sin(\theta)-1]=0$
Doesn't follow.
Distribute the terms in the bottom expression to test if they're equal.