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# Trig Watch

1. the limits are

cos(3x-10)=-0.4

i did this for the limits, is this right?

2. (Original post by thefatone)
i did this for the limits, is this right?
Nopes. If then
3. (Original post by Zacken)
Nopes. If then
but surely if i have an answer of -10 (just an example) then if i add 10 then divide by 3 then the answer would be in the limit of

wouldn't it?
4. (Original post by thefatone)
but surely if i have an answer of -10 (just an example) then if i add 10 then divide by 3 then the answer would be in the limit of

wouldn't it?

I dunno what you're saying, but I advise that you look up solving linear equations.

It's like you're telling me that
5. (Original post by Zacken)
I dunno what you're saying, but I advise that you look up solving linear equations.

It's like you're telling me that
not quite

i'm trying to say that if you have 3x-10=0 then on the left side then on the right side you must add 10

so this

thus
6. (Original post by thefatone)
not quite

i'm trying to say that if you have 3x-10=0 then on the left side then on the right side you must add 10

so this

thus
What?

When you add 10 you get:

7. (Original post by Zacken)
What?

When you add 10 you get:

i see, so then i multiply by 3 after that?
8. (Original post by thefatone)
i see, so then i multiply by 3 after that?
DIVIDE by .
9. (Original post by Zacken)
DIVIDE by .
this is very confusing... but then when i get my values for
cos(3x-10)=-0.4

i wouldn't include like values any bigger than 63.3°
10. (Original post by thefatone)
this is very confusing... but then when i get my values for
cos(3x-10)=-0.4

i wouldn't include like values any bigger than 63.3°
Yes, precisely. (also you wouldn't include values smaller than 3.33)
11. (Original post by Zacken)
Yes, precisely. (also you wouldn't include values smaller than 3.33)
wat... that's not working with my logic and "correct" answers

here have the question and mark scheme

https://a44694f152ee562e38a9454969d2...%20Edexcel.pdf
question 4

mark scheme is in the pages far down
12. (Original post by thefatone)
wat... that's not working with my logic and "correct" answers

here have the question and mark scheme

https://a44694f152ee562e38a9454969d2...%20Edexcel.pdf
question 4

mark scheme is in the pages far down

We have:
13. (Original post by Zacken)

We have:
so you multiply first then takeaway the 10???
14. (Original post by thefatone)
so you multiply first then takeaway the 10???
Yeah.
15. (Original post by Zacken)
Yeah.
Thanks for clearing that up
16. (Original post by thefatone)
Thanks for clearing that up
No problem.

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