Answer:
Proved See below
Step-by-step explanation:
Man this one is a world of its own :D Just a quick question are you a fellow Add Math student in O levels i remember this question from back in the day :D Anyhow Lets get started
For this question we need to know the following identities:

Lets solve the bottom most part first:

Take LCM

now break the LCM

because 1/tan = cot x
and furthermore,

now we solve the above part and replace the bottom most part that we solved with 

Hence proved! :D
The water levels at high tide was 9 feet and 1 foot at low tide
Answer:
We have sin² x + cos² x =1 for all real x.
Therefore, sin² x = 1 – cos² x = 1 – (8/17)² = 1 – 64/289 = 225/289 = (15/17)².
However, remember that if x² = a², then x can be +a or –a.
Therefore, sin x can be either –15/17 or +15/17.
Everyone but Anirban so far has forgotten the negative solution.
Step-by-step explanation:
Given that sinθ=817 and cosθ<0 , we have: cosθ=−√1−sin2θ. cosθ=−√1−(817)2. cosθ=−√1−64289.
I got x= 63/59
i used mathpapa.com for these questions hoped this is right and helped