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March 29, 2024, 04:32:39 am

Author Topic: 3U Maths Question Thread  (Read 1230330 times)  Share 

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RuiAce

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Re: 3U Maths Question Thread
« Reply #1215 on: January 14, 2017, 10:11:25 am »
0


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« Last Edit: January 14, 2017, 10:27:21 am by RuiAce »

anotherworld2b

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Re: 3U Maths Question Thread
« Reply #1216 on: January 14, 2017, 02:37:35 pm »
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Could i have help with this question please? I was able to do part a.
« Last Edit: January 14, 2017, 02:39:38 pm by anotherworld2b »

jamonwindeyer

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Re: 3U Maths Question Thread
« Reply #1217 on: January 14, 2017, 02:44:29 pm »
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Could i have help with this question please?

Sure! Both B and C are asking you to examine the discriminant of the quadratic factor in the polynomial, that is, \(x^2-3x+c\). The discriminant in this case is \(b^2-4ac=9-4c\).

Remember, if the discriminant is equal to zero, there is a single root for the quadratic. If it is greater than zero, there are two roots.

For the whole function, the number of roots is \(1+n\) where \(n\) is the number of roots for the quadratic (because there is a single root from that linear factor out the front either way). So you'll end up with a few inequalities! See if that helps you move towards an answer - Let me know if it doesn't ;D

The last question needs simultaneous equations:



Those two equations, solved simultaneously, will give you the answers you need! ;D

Let me know if this helps :)

Rathin

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Re: 3U Maths Question Thread
« Reply #1218 on: January 20, 2017, 01:25:44 pm »
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When doing integration by substitution for indefinite integrals do the boundaries always swap around when you integrate in terms of u or do you have to sub the values of x into the substitution of 'u' ( a function u(x) ) and check the boundaries that are produced for the variable u everytime?
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jamonwindeyer

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Re: 3U Maths Question Thread
« Reply #1219 on: January 20, 2017, 02:12:21 pm »
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When doing integration by substitution for indefinite integrals do the boundaries always swap around when you integrate in terms of u or do you have to sub the values of x into the substitution of 'u' ( a function u(x) ) and check the boundaries that are produced for the variable u everytime?

You need to substitute the values of \(x\) and check the resultant value of \(u\) every time :)

bholenath125

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Re: 3U Maths Question Thread
« Reply #1220 on: January 20, 2017, 04:59:08 pm »
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I don't exactly understand
How parametrics works

Could someone explain

(the whole thing) please

anotherworld2b

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Re: 3U Maths Question Thread
« Reply #1221 on: January 20, 2017, 05:06:45 pm »
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Hi i was wondering can I please get help with these questions please? I tried q34 but i cant get the answer. I am having difficulty with the diagram for q35

jamonwindeyer

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Re: 3U Maths Question Thread
« Reply #1222 on: January 20, 2017, 05:22:19 pm »
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I don't exactly understand
How parametrics works

Could someone explain

(the whole thing) please

Hey! If you scroll to the bottom of this guide I wrote you'll find a summary of parametric, including some examples to demonstrate the principles. It should help you get the basic idea! Feel free to send any specific problems you are struggling with our way :)

jamonwindeyer

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Re: 3U Maths Question Thread
« Reply #1223 on: January 20, 2017, 05:37:38 pm »
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Hi i was wondering can I please get help with these questions please? I tried q34 but i cant get the answer. I am having difficulty with the diagram for q35

Hey! Both of these rely on the sine rule.

You were on the right track for Q34! But you don't need the smaller triangle, and you made a little mistake with the angles at the top there. Be careful! Here is my diagram and working:

Question 34


Here is the diagram for Q35 as I interpret it (the question isn't worded that well imo) - Attack it with the sine rule as well :)

Question 35


anotherworld2b

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Re: 3U Maths Question Thread
« Reply #1224 on: January 20, 2017, 06:35:38 pm »
+1
thank you for your help :)
Hey! Both of these rely on the sine rule.

You were on the right track for Q34! But you don't need the smaller triangle, and you made a little mistake with the angles at the top there. Be careful! Here is my diagram and working:

Question 34


Here is the diagram for Q35 as I interpret it (the question isn't worded that well imo) - Attack it with the sine rule as well :)

Question 35


anotherworld2b

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Re: 3U Maths Question Thread
« Reply #1225 on: January 20, 2017, 07:43:09 pm »
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Can i have help with this question please? I am not sure where to start  :-\

jakesilove

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Re: 3U Maths Question Thread
« Reply #1226 on: January 21, 2017, 08:43:38 am »
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Can i have help with this question please? I am not sure where to start  :-\

Start by drawing lines from the center to the circumference, at the point that the line beams touch the circle. Both of these lines are the radius, and so have the same length. We also know that the LENGTH of the two beams of light are equal (I call this one the ice cream cone rule). Plug all that in, and you'll have two congruent triangles. Try using some rules (cosine, sin, adding extra lines to draw triangles) to get some angles out; you're looking for the angle at the centre of the circle. Once you have that, you can use l=theta*r to get the arc enclosed by the angle, and then put that over the total circumference.
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jamonwindeyer

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Re: 3U Maths Question Thread
« Reply #1227 on: January 21, 2017, 10:10:35 am »
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We also know that the LENGTH of the two beams of light are equal (I call this one the ice cream cone rule).

Just letting you know I wiill almost definitely steal this  8)

anotherworld2b

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Re: 3U Maths Question Thread
« Reply #1228 on: January 21, 2017, 11:11:34 am »
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Thank you for your help :)
I was also wondering if i could get help with these question. I am not sure why but i struggle to understand how to draw the diagrams.

Start by drawing lines from the center to the circumference, at the point that the line beams touch the circle. Both of these lines are the radius, and so have the same length. We also know that the LENGTH of the two beams of light are equal (I call this one the ice cream cone rule). Plug all that in, and you'll have two congruent triangles. Try using some rules (cosine, sin, adding extra lines to draw triangles) to get some angles out; you're looking for the angle at the centre of the circle. Once you have that, you can use l=theta*r to get the arc enclosed by the angle, and then put that over the total circumference.

jamonwindeyer

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Re: 3U Maths Question Thread
« Reply #1229 on: January 21, 2017, 02:26:18 pm »
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Thank you for your help :)
I was also wondering if i could get help with these question. I am not sure why but i struggle to understand how to draw the diagrams.

These diagrams may be a tad confusing depending on how you have been taught to use the angles of any magnitude system, let me know! :)