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    f(x)=tanx+1-4x,Π/2<X<Π/2
    Show that f(x)=0 has a root in the interval [1.42,1.44]
    I tried to put calculator in radian mode but it didn't work
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    (Original post by alesha98)
    f(x)=tanx-1-4x,Π/2<X<Π/2
    Show that f(x)=0 has a root in the interval [1.42,1.44]
    I tried to put calculator in radian mode but it didn't work
    Fixed it for you.
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    (Original post by alesha98)
    f(x)=tanx+1-4x,Π/2<X<Π/2
    Show that f(x)=0 has a root in the interval [1.42,1.44]
    I tried to put calculator in radian mode but it didn't work
    http://www.thestudentroom.co.uk/forumdisplay.php?f=38
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    (Original post by alesha98)
    f(x)=tanx+1-4x,Π/2<X<Π/2
    Show that f(x)=0 has a root in the interval [1.42,1.44]
    I tried to put calculator in radian mode but it didn't work
    What's f(1.42)?

    What's f(1.44)?

    What do you mean your calculators radian mode isn't working?

    Moved to maths.
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    You know it's continuous due to the domain of the function, so just check f(1.42) and f(1.44) and if there's a change of sign then there must be a root within the interval.
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    (Original post by Zacken)
    What's f(1.42)?

    What's f(1.44)?

    What do you mean your calculators radian mode isn't working?

    Moved to maths.
    I got f(1.42)=19011 but it isnt the answer
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    (Original post by alesha98)
    I got f(1.42)=19011 but it isnt the answer
    What are you putting into your calculator?
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    (Original post by alesha98)
    f(x)=tanx+1-4x,Π/2<X<Π/2
    Show that f(x)=0 has a root in the interval [1.42,1.44]
    I tried to put calculator in radian mode but it didn't work
    (Original post by EricPiphany)
    Fixed it for you.
    ^^ notice you wrote "+1", however it should be "-1" as the above poster said.
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    I double checked from the book and the question is tanx+1-4x.
    I put calculator in radian mode:tan1.42+1-4(1.42)
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    (Original post by alesha98)
    I double checked from the book and the question is tanx+1-4x.
    I put calculator in radian mode:tan1.42+1-4(1.42)
    That's a typo in the book then. It works with tan(x)-1-4x (root at ~1.422).
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    (Original post by alesha98)
    I double checked from the book and the question is tanx+1-4x.
    I put calculator in radian mode:tan1.42+1-4(1.42)
    its probably a mistake in the book, answer tanx - 1 -4x instead

     \displaystyle \tan(1.42)\: \text{and}\: \tan(1.44) \approx 7 so it must be -1 instead of +1
 
 
 
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