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Hey so,

When a question asks why does say f(x) have an inverse function, where f(x)=x^3 or something like that, is all you have to say to get full marks, because for every x value there is one y value?

Also in circle geo, can you just say thales' theorem instead of angles in a semicircle are 90
 

RivalryofTroll

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Hey so,

When a question asks why does say f(x) have an inverse function, where f(x)=x^3 or something like that, is all you have to say to get full marks, because for every x value there is one y value?

Also in circle geo, can you just say thales' theorem instead of angles in a semicircle are 90
For every y-value, there is only 1 x-value too.

Angle in semi-circle is right angle is more universally accepted.
 

Trebla

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Also, a function with a unique inverse is monotonic (ie there is no change in sign of the gradient). Note that in your example the derivative is non-negative.
 

Makematics

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i wouldnt recommend saying thales theorem. i have done a fair bit of circle geometry and have not heard of it. stick to angle in a semi-circle in the hsc for sure. maybe your school might except thales theorem though
 

RealiseNothing

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Also if you got marked down in the HSC for writing Thale's Theorem, I'd really question the integrity of the marker and why they are even allowed to mark HSC responses.
 

hayabusaboston

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Hey so,

When a question asks why does say f(x) have an inverse function, where f(x)=x^3 or something like that, is all you have to say to get full marks, because for every x value there is one y value?

Also in circle geo, can you just say thales' theorem instead of angles in a semicircle are 90
we got a badass over here!!
 

Makematics

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ive never seen the words thale's theorem in any major textbook (terry lee, fitzpatrick, cambridge). But even if the marker sees thale's theorem they can either search up to verify that it is the same or they can ask the head marker. usually with things like this i write the more formal words such as angle in a semi-circle just to be sure, and it only takes 1 or 2 seconds of your time.
 

hayabusaboston

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ive never seen the words thale's theorem in any major textbook (terry lee, fitzpatrick, cambridge). But even if the marker sees thale's theorem they can either search up to verify that it is the same or they can ask the head marker. usually with things like this i write the more formal words such as angle in a semi-circle just to be sure, and it only takes 1 or 2 seconds of your time.
this is why I said we got a badass over here. He is discreetly trying to show off that he in fact knows more sophisticated terminology than you in maths and thus is implying he is really good and probably better than you at maths, all done very sneakily hahaha, so as to not make people hate him. WELL M8 WE CAN TELL UR A MATHS ENTHUSIAST, but there are people on here better than u, so dont be up urself. Better check urself b4 u wreck urself m8 hahaha
 

RealiseNothing

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this is why I said we got a badass over here. He is discreetly trying to show off that he in fact knows more sophisticated terminology than you in maths and thus is implying he is really good and probably better than you at maths, all done very sneakily hahaha, so as to not make people hate him. WELL M8 WE CAN TELL UR A MATHS ENTHUSIAST, but there are people on here better than u, so dont be up urself. Better check urself b4 u wreck urself m8 hahaha
His question was a legitimate question. It is more widely known as Thale's Theorem and is not at all more "sophisticated terminology", it's like asking when describing the tangent-secant theorem, can you just call it that or have to explain what it means.
 

Carrotsticks

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You may use Thales' Theorem, it will be accepted in the HSC. If the marker is not aware of the term, they will contact the senior marker for advice. This is similar to Biology, where some students try to make up examples to suit their answer. The markers have access to the internet, and will search up the 'example' provided, if it is unfamiliar.

However, that may not be the case with your internal school assessments.
 

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