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# Confused about FP1 question - matrices, MEI watch

1. Hey, this is a very specific question mostly just about trying to decipher what the textbook wants exactly? basically, im trying to do FP1, MEI, EX 1E, QS 4.
even if you dont have a textbook on hand someone might be able to work this out hah
basically, i have been given a triangle, a matrix to transform it, and i have found the transformed triangle

ive been asked to find the area of the original triangle, the area of the transformed triangle, and find the ratio between the two.i was wondering if maybe there was a way of finding out such a thing using a matrix, but hadnt seen anything. so i thought since it looked like a lower mark sort of question it should be pretty simple. i know if its what i was meant to do with just whichever longwinded method i could i would be able to do it but generally i find these questions are pretty simple and are meant to only test you on the new concepts rather than something random like, can you calculate the area of a triangle. but both the triangles are awkward, non right angle, scalene triangles. i looked at the tips specific for this question on the mei integral maths website and it says 'find the areas using 1/2 x base x height' but i thought that only works on right angled triangles. also i dont know the side lengths or any angles.

sorry if im an idiot for being troubled by this i just feel like i must be missing some easier method and i dont know why theyd set a question up like this. should i just go with it?

honestly im probably making no sense, im a bit under the weather and cant think straight. will probably be clearer if i leave it and come back again later when i dont have a headache but if not id like to hear what other people think if its even possible to sift meaning from my nonsense babbling
2. (Original post by EmergencyBagels)
Hey, this is a very specific question mostly just about trying to decipher what the textbook wants exactly? basically, im trying to do FP1, MEI, EX 1E, QS 4.
even if you dont have a textbook on hand someone might be able to work this out hah
basically, i have been given a triangle, a matrix to transform it, and i have found the transformed triangle

ive been asked to find the area of the original triangle, the area of the transformed triangle, and find the ratio between the two.i was wondering if maybe there was a way of finding out such a thing using a matrix, but hadnt seen anything. so i thought since it looked like a lower mark sort of question it should be pretty simple. i know if its what i was meant to do with just whichever longwinded method i could i would be able to do it but generally i find these questions are pretty simple and are meant to only test you on the new concepts rather than something random like, can you calculate the area of a triangle. but both the triangles are awkward, non right angle, scalene triangles. i looked at the tips specific for this question on the mei integral maths website and it says 'find the areas using 1/2 x base x height' but i thought that only works on right angled triangles. also i dont know the side lengths or any angles.

sorry if im an idiot for being troubled by this i just feel like i must be missing some easier method and i dont know why theyd set a question up like this. should i just go with it?

honestly im probably making no sense, im a bit under the weather and cant think straight. will probably be clearer if i leave it and come back again later when i dont have a headache but if not id like to hear what other people think if its even possible to sift meaning from my nonsense babbling
If you could post the pic it would help because im not understanding what you wrote, sorry:/

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3. I think the ratio between the two should be the determinant of the transformation matrix.
4. (Original post by EmergencyBagels;[url="tel:66466946")
66466946[/url]]Hey, this is a very specific question mostly just about trying to decipher what the textbook wants exactly? basically, im trying to do FP1, MEI, EX 1E, QS 4.
even if you dont have a textbook on hand someone might be able to work this out hah
basically, i have been given a triangle, a matrix to transform it, and i have found the transformed triangle

ive been asked to find the area of the original triangle, the area of the transformed triangle, and find the ratio between the two.i was wondering if maybe there was a way of finding out such a thing using a matrix, but hadnt seen anything. so i thought since it looked like a lower mark sort of question it should be pretty simple. i know if its what i was meant to do with just whichever longwinded method i could i would be able to do it but generally i find these questions are pretty simple and are meant to only test you on the new concepts rather than something random like, can you calculate the area of a triangle. but both the triangles are awkward, non right angle, scalene triangles. i looked at the tips specific for this question on the mei integral maths website and it says 'find the areas using 1/2 x base x height' but i thought that only works on right angled triangles. also i dont know the side lengths or any angles.

sorry if im an idiot for being troubled by this i just feel like i must be missing some easier method and i dont know why theyd set a question up like this. should i just go with it?

honestly im probably making no sense, im a bit under the weather and cant think straight. will probably be clearer if i leave it and come back again later when i dont have a headache but if not id like to hear what other people think if its even possible to sift meaning from my nonsense babbling
Just post a pic. Definitely sounds like you are babbling nonsense
5. I'm pretty sure the scale factor of enlargement of a triangle transformed by a matrix is the determinant

yea, what was said a couple of posts before me
6. this is it
Attached Images

7. (Original post by TheAlphaParticle)
this is it
The determinant of the matrix tells you the area scale factor between the transformed and the original shape. (For 2x2 matrices at least).
8. As people said before.
1)You can work out the area of triangle by using its coords
2) Find theDeteminant of the matrix
3)Area if original triangle * Deteminant =Area of new triangle

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9. Multiply Det by area of original triangle for area of new triangle. or do 1/2bh but that takes longer
10. right, sorry, thanks all, and thanks for posting the pic. this all makes sense. just was being neurotic and silly really so thanks for the help

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