Had a maths problem in my final Year 11 Exam (2 unit) (1 Viewer)

[jadenmaccas]

Hey guys. I'm in Year 10 accelerating 2 unit maths and I came across a trigonomic identity which I found almost impossible to prove. After the exam, I heard that you have to 'cross-multiply' to solve it by some students in Year 11. I never came across this before. Isn't it just LHS = RHS? I couldn't prove the identity correctly.

Here is the question: http://latex.codecogs.com/gif.latex?\frac{1}{\csc%20x%20+%20\cot%20x}%20=%20\csc%20x%20-%20\cot%20x

 

[nightweaver066]

Multiplying everything by sin^2x

 

[kooliskool]

Hi, it's actually pretty simple, no need to do "cross-multiply" or anything, LHS=....=RHS is the correct way, think of the relationship between cosec and cot:









since

 

[jadenmaccas]

Multiplying everything by sin^2x

Nightweaver, read the question -.-

 

[nightweaver066]

Mistake in the working out third last line.. Corrected.

 

[cutemouse]

What school do you go to?

 

[maths lover]

this was in my prelims as well, this is an independent question.