"O" level E.Maths students tend to think only about TOA CAH SOH
for acute angle only.
In fact, there is the TOA CAH SOH for obtuse angle too.
tan angle EBC is an obtuse angle TOA.
Hence, tan angle EBC = - 5/12.
PS : "O" level Add Maths students will know that TOA CAH SOH can
be for all 4 quadrants ie the famous ASTC (add sugar to coffee, all
science teachers are crazy etc) rule.
very true
need to help switch their mindset to include obtuse angles too
Finding AD also very important... using areas...
Not only used here, many other question types as well...
