Maths C3 - Trigonometry... Help??

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    (Original post by RDKGames)
    \displaystyle a=4\sec(x)=4(\frac{1}{\cos(x)})=  4(\frac{1}{b}) and proceed from there
    Oh wow. I prefer your way to mine! Thaannnnk you!!...

     a = 4 \sec x

     a = 4 (\frac{1}{cos x})

     a = 4 (\frac{1}{b})

     a = \frac{4}{b}

     ab = 4

     b = \frac{4}{a}
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    (Original post by B_9710)
    That's right.
    Thanks a lot for your help
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    (Original post by Philip-flop)
    Attachment 581928
    Ok so for part b my basic Maths knowledge seems to be letting me down. I've solved this up until...

     c^2 = \frac {(\frac{16}{a^2})}{1 - (\frac{16}{a^2})}

    But then I'm not quite sure how to simplify it from there. The denominator scares me a little
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    (Original post by Philip-flop)
    Ok so for part b my basic Maths knowledge seems to be letting me down. I've solved this up until...

     c^2 = \frac {(\frac{16}{a^2})}{1 - (\frac{16}{a^2})}

    But then I'm not quite sure how to simplify it from there. The denominator scares me a little
    Multiply the fraction by \displaystyle \frac{a^2}{a^2}
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    (Original post by RDKGames)
    Multiply the fraction by \displaystyle \frac{a^2}{a^2}
    And that'll give me...


     c^2 = \frac{16}{a^2 - 16} .... right?

    How did you know to multiply by  \frac{a^2}{a^2} ?? I'm not sure I know how to properly

    Edit: also, just wondering.. How do you increase the font of just the text written in latex form?
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    (Original post by Philip-flop)
    And that'll give me...


     c^2 = \frac{16}{a^2 - 16} .... right?

    How did you know to multiply by  \frac{a^2}{a^2} ?? I'm not sure I know how to properly
    Yep, and I knew I had to multiply by that because I wanted the (second) denominator to go away, so I had to choose a^2. I cannot multiply only one term, so I had to multiply through the whole denominator by it. If I'm multiplying through the whole denominator, I must also multiply the whole numerator by the same thing. Hence a^2 on both.
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    (Original post by RDKGames)
    Yep, and I knew I had to multiply by that because I wanted the (second) denominator to go away, so I had to choose a^2. I cannot multiply only one term, so I had to multiply through the whole denominator by it. If I'm multiplying through the whole denominator, I must also multiply the whole numerator by the same thing. Hence a^2 on both.
    Wow you really are a Maths wizard to me!! Are there any good videos/resources dealing with algebraic fractions when there are more than one term in the denominator and where there are fractions in the numerator and denominator? It's definitely something I need to work on
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    Just to add on to the above post, remember  \frac{a^2}{a^2} is just 1...

    so you're not changing the value, you're just changing its form/appearance...
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    (Original post by Philip-flop)
    Wow you really are a Maths wizard to me!! Are there any good videos/resources dealing with algebraic fractions when there are more than one term in the denominator and where there are fractions in the numerator and denominator? It's definitely something I need to work on
    r u srs u did this in chapter 1
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    (Original post by Philip-flop)
    Wow you really are a Maths wizard to me!! Are there any good videos/resources dealing with algebraic fractions when there are more than one term in the denominator and where there are fractions in the numerator and denominator? It's definitely something I need to work on
    Not really, it's nothing significant enough to make videos about, just a simple manipulation you get used to when you deal with enough of these cases.
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    (Original post by Naruke)
    r u srs u did this in chapter 1
    In these kind of cases I'm not that comfortable with it

    I never would have known to multiply by..  \frac{a^2}{a^2}...for the example above.

    (I know my Maths knowledge sucks but I never said I was a natural)
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    (Original post by Philip-flop)
    In these kind of cases I'm not that comfortable with it

    I never would have known to multiply by..  \frac{a^2}{a^2}...for the example above.

    (I know my Maths knowledge sucks but I never said I was a natural)
    The reason why maths is such a great thing is because there are so many ways to go about solving problems. What that RDK kid did above was just one way of solving it...

    You could have easily just did

     c^2 \equiv \frac{\frac{16}{a^2}}{1-\frac{16}{a^2}}
    (common denominators, you learned this in the earlier chapters to!) c^2 \equiv \frac{\frac{16}{a^2}}{\frac{a^2 - 16}{a^2}}
     c^2 \equiv \frac{16}{a^2} \times \frac{a^2}{a^2 - 16} (You probably learned this in KS1...  \frac{\frac{a}{b}}{\frac{c}{d}} \Rightarrow \frac{a}{b} \times \frac{d}{c})
    from there it's just a simple case of cancelling the  a^2 and multiplying.

    I don't think there is a lot of gaps in your knowledge. I think you just need to practice using the skills you've acquired in previous chapters in unusual circumstances.
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    (Original post by Naruke)
    The reason why maths is such a great thing is because there are so many ways to go about solving problems. What that RDK kid did above was just one way of solving it...
    Okay, kid, lay off the identity signs, the expressions aren't identical
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    (Original post by RDKGames)
    Okay, kid, lay off the identity signs, the expressions aren't identical
    lmao

    this is a free country I'm allowed to use any sign I want

    leave me alone
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    (Original post by Naruke)
    lmao

    this is a free country I'm allowed to use any sign I want

    leave me alone
    I bet you're a Trump supporter who wants to deport all those awkward division signs with a line and two dots.
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    (Original post by RDKGames)
    Okay, kid, lay off the identity signs, the expressions aren't identical
    Why?

    The 'c' and 'a' are substitutions so it's not really a problem calling it an identity IMO.
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    (Original post by RDKGames)
    Okay, kid, lay off the identity signs, the expressions aren't identical
    Huh?
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    (Original post by notnek)
    Why?

    The 'c' and 'a' are substitutions so it's not really a problem calling it an identity IMO.
    (Original post by Zacken)
    Huh?
    lol you guys....
    Spoiler:
    Show
    I was kidding
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    (Original post by RDKGames)
    lol you guys....
    Spoiler:
    Show
    I was kidding
    Didn't want to embarrass you but it seems they have

    it's a shame really
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    (Original post by Naruke)
    Didn't want to embarrass you but it seems they have

    it's a shame really
    Oh definitely :getmecoat:

    I mean I expected it from Zacken but Notnek was surprising
 
 
 
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