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Mathematics: Post your doubts here!

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HELP
A committee of 5 people is to be chosen from 6 men and 4 women. In how many ways can this be done
(iii) if there must be 3 men and 2 women, and one particular woman refuses to be on the committee with one particular man?
 
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v1 = 0.02t + 1

v1 - v = 0.02t+1 - (0.04t − 0.000 05t^2)
= 0.02t + 1 - 0.04t + 0.00005t^2
= 0.00005t^2 - 0.02t + 1
= 0.00005(t^2 - 400t + 20000)
= 0.00005[t^2 - 400t + 200^2 - 200^2 + 20000]
= 0.00005[(t - 200)^2 - 20000]
= 0.00005(t - 200)^2 - 1
Thnx for replying...........but I dont get the v1, how did u find it?
:)
 
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Thnx for replying...........but I dont get the v1, how did u find it?
:)
v1 is the first part of the graph. So we simply need it's equation.
gradient = (9-1)/(400-0) = 0.02
y - intercept = 1
So v1 = 0.02t + 1

Or alternatively,
v = u+at,
Where u=1, a=0.02
v1 = 1 + 0.02t
 

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v1 is the first part of the graph. So we simply need it's equation.
gradient = (9-1)/(400-0) = 0.02
y - intercept = 1
So v1 = 0.02t + 1

Or alternatively,
v = u+at,
Where u=1, a=0.02
v1 = 1 + 0.02t
Thanku sooo much!!
God, it was that easy.................. I feel dumb! :D
 
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(i) f(x) = 4, so: 6 - 4cos(0.5x) = 4
cos(0.5x) = 0.5
0.5x = π / 3 (since it says exact, no need for basic angles and stuff)
x = 2π / 3

(ii) Max = a + b = 6+4 = 10 and Min = a - b = 6 - 4 = 2
So, range: 2 <f(x)<10

(iii) The graph is going to be upside down since the cos is -ve.............. so it would be something like this: (sorry for the crappy drawing though)
View attachment 57098

(iv) The inverse is just like the normal one

Hope it helps............... :)
Sorry for the late reply. Could you explain how did you get the exact value of the inverse of cos 0.5?
 
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Sorry for the late reply. Could you explain how did you get the exact value of the inverse of cos 0.5?
These are the common angles and their trigonometric ratios you should try to learn:

6965817_f520.jpg


As you can see, cos^-1(0.5) = 60°, or π/3 radians.
 
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(i) f(x) = 4, so: 6 - 4cos(0.5x) = 4
cos(0.5x) = 0.5
0.5x = π / 3 (since it says exact, no need for basic angles and stuff)
x = 2π / 3

(ii) Max = a + b = 6+4 = 10 and Min = a - b = 6 - 4 = 2
So, range: 2 <f(x)<10

(iii) The graph is going to be upside down since the cos is -ve.............. so it would be something like this: (sorry for the crappy drawing though)
View attachment 57098

(iv) The inverse is just like the normal one

Hope it helps............... :)
Yeah I understood it. Thanks a lot for your help!
 
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A small doubt..
According to grade threshold of 2015
To get A we should get at least 62 in paper 1 and 42 in paper 6
So my doubt is In paper 1 I scored 68 and in paper 6 I scored 30.
What will be my grade?? C or B or A ?
 
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Ummmm..............can anyone help me with moi doubt: (The paper is w07 qp 4)

Capture.PNG

The marking scheme says that s1 + s2 = 10, I dont get that................. I came to the conclusion that it would be s1 - s2 = 10................ so can anyone explain why it is like that? :D
 
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