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    My stomach is so quaky at the thought of this exam, it makes C3 look like a puppy. I think I have full UMS in C3 and if this one costs me the A* after that I will rip my hair out
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    (Original post by paradoxicalme)
    My stomach is so quaky at the thought of this exam, it makes C3 look like a puppy. I think I have full UMS in C3 and if this one costs me the A* after that I will rip my hair out
    What do you dislike about C4 in comparison to C3?
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    c4 is actually killing me, my accuracy's dropped so much from c3... TAT
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    (Original post by 13 1 20 8 42)
    What do you dislike about C4 in comparison to C3?
    -Far more nuances to it, lots of little things to forget. I'm pretty comfortable with integration on the whole but little things like the integration version of the chain rule are easy to screw up on
    -Mostly, I'm annoyed by how there are so many big-mark questions that can be so easily screwed up. Take a tricky volumes of revolution question. You could do all the method perfectly, but accidentally miscalculate the limits or take out a 0 somewhere at the beginning and that could be 6 marks down the tube
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    (Original post by paradoxicalme)
    -Far more nuances to it, lots of little things to forget. I'm pretty comfortable with integration on the whole but little things like the integration version of the chain rule are easy to screw up on
    -Mostly, I'm annoyed by how there are so many big-mark questions that can be so easily screwed up. Take a tricky volumes of revolution question. You could do all the method perfectly, but accidentally miscalculate the limits or take out a 0 somewhere at the beginning and that could be 6 marks down the tube
    Fair points
    I guess of all the cores it emphasises meticulousness the most
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    Could someone help me with a question please? Its question 3 on page 142 of the heinmann textbook. I tried uploading my working but my phone is being an idiot. I differentiated sectheta to be secthetatantheta and used the trig identity sec^2theta=1+tan^2theta but i've got a weird answer of integral of sectheta/tan^2theta.
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    Which areas/volumes do we need to know?
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    http://www.thestudentroom.co.uk/show....php?t=3361905
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    when do we use integration by inspection?
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    (Original post by blueberry389)
    when do we use integration by inspection?
    On a crime scene


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    Why have I worked out the obtuse angle as opposed to the acute? It didnt specify that the angle was acute so I didnt mod it
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    You need to use AC and BC, not AC and CB. To find a specific angle you use either two vectors heading into the angle, or two vectors both heading away from the angle
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    (Original post by jubilant_joej)
    You need to use AC and BC, not AC and CB. To find a specific angle you use either two vectors heading into the angle, or two vectors both heading away from the angle
    Oh! okay great, cheers fella! Didn't know that.
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    Guys on question 2b how do you know which range of x values to use, I've got |X| <1 and |X| <1/4 but I don't know which one is correct, the mark scheme it says something about 'tightest' what does that mean? Thanks in advance

    Here's link: http://www.madasmaths.com/archive/iy...apers/c4_n.pdf
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    keep up the spirit guys!
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    (Original post by MasonPye)
    Guys on question 2b how do you know which range of x values to use, I've got |X| <1 and |X| <1/4 but I don't know which one is correct, the mark scheme it says something about 'tightest' what does that mean? Thanks in advance

    Here's link: http://www.madasmaths.com/archive/iy...apers/c4_n.pdf
    The tightest condition is the strictest one. Let's say we have two conditions: x must be less than 10, and x must be less than 4. For both of those conditions to be satisfied, x must be less than 4, because if x is less than 4, then x is less than 10.

    mod(x) is similar. If mod(x) < 1 and mod(x) < 1/4, then which one is the inequality such that both of them are satisfied?
    (Original post by blueberry389)
    when do we use integration by inspection?
    (Usually) when nothing else seems to work, but if you can use it then you should be able to spot it. Eg (sin3x)^2 * cos3x, it's something * the differential of it, so you could guess that the integral is similar to (sin3x)^3, then account for the 3x by dividing by 1/3, so the integral is 1/3(sinx)^3.

    I think they explain it more formally in the textbook with notation that can be difficult to understand. You use it when you think 'okay, what differentiates to give the thing I'm integrating?'

    Another example would be (4x+10)/(x^2 + 5x + 10). Seeing as the top is a multiple of the differential of the bottom, you could guess that it was lnmod(x^2 + 5x + 10), so when you differentiate that you get 2x+5/(x^2+5x+10), so you need to double the integral to get the differential, so the answer is 2lnmod(x^2+5x+10).


    (Original post by kobobo)
    Could someone help me with a question please? Its question 3 on page 142 of the heinmann textbook. I tried uploading my working but my phone is being an idiot. I differentiated sectheta to be secthetatantheta and used the trig identity sec^2theta=1+tan^2theta but i've got a weird answer of integral of sectheta/tan^2theta.
    Sometimes writing things out in terms of sin and cos are the way to go, like in this case. Once you've done that it should be a bit clearer which integration method you use.
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    Any tips for vectors questions?
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    (Original post by anonwinner)
    Any tips for vectors questions?
    Diagram=sorted.


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    (Original post by physicsmaths)
    Diagram=sorted.


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    Second that. Wouldn't be able to do vectors without a diagram - doesn't have to be accurate, just enough to see whats going on. Always do a huge one right at the start of the Q - helpful to look ahead though to leave room for other bits
 
 
 
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