IGCSE MATHS Doubts

[Fastal]

uh im sorry
i dont really get it
how did u get -7?

i think its +9

[@d!_†oX!©]

uh im sorry
i dont really get it
how did u get -7?

see, first u substracct and then take the lcm
it is
+9-16 which is equal to -7
(x-3)/4  -  4/(x-3) = 0
then take lcm
so,
(x-3)(x-3) - 4*4 / 4x - 12 = 0
x² -3x -3x +9 -16 / 4x-12 = 0
so the simplify and get
x² - 6x -7 / 4x -12 = 0

[Vin]

uh im sorry
i dont really get it
how did u get -7?

(x-3) (x-3) - 16
------------------
   4x -12


x² -6x + 9 - 16
------------------
   4x -12

x² - 6x -7
------------------
   4x -12

[Vin]

Ok guys i hav a doubt .. after a long time ..

[ksitna]

see, first u substracct and then take the lcm
it is
+9-16 which is equal to -7
(x-3)/4  -  4/(x-3) = 0
then take lcm
so,
(x-3)(x-3) - 4*4 / 4x - 12 = 0
x² -3x -3x +9 -16 / 4x-12 = 0
so the simplify and get
x² - 6x -7 / 4x -12 = 0

the mark scheme says

x2-6x+25/4(x-3) :/

[Ghost Of Highbury]

310 degrees and 230 degrees

check if its correct in the ms.

sin x = -0.76

x = sin^-1(0.76) = -50

x = 360-50 = 310

x = 180+50 = 230.

@ksitna - adi_toxic and vin1094 are correct. 4(x-3) = 4x-12. same hing

[ksitna]

310 degrees and 230 degrees

check if its correct in the ms.

sin x = -0.76

x = sin^-1(0.76) = -50

x = 360-50 = 310

x = 180+50 = 230.

@ksitna - adi_toxic and vin1094 are correct. 4(x-3) = 4x-12. same hing

no i meant they got -7

not 25

[Vin]

oooohh Thanks .. its absolutely correct!! no wonder ur smart !! i really admire u ..

[Ghost Of Highbury]

@vin - thanks, check ur inbox SF  pal..

@ksitna - ohk, ill check

[Ghost Of Highbury]

they arent wrong, the ms cant be wrong, which paper is this q from??

[ksitna]

june 07 p2

[Fastal]

the question is actually an expression

(x-3/4) + (4/x-3)

so here its
x² + 9 - 6x + 16/4x-12

so you get +25

[@d!_†oX!©]

I know you got this already, but i don't mind elaborating  

        90  
     S  |  A
180----------0/360
     T  |  C  
       270
Read the above as follows before starting:
1) A=All +ve , S= Sin +ve , T=Tan +ve , C=Cos +ve
2) This shows the four quadrants, going anticlockwise from 0 to 90 to 180 270 to 360.
3) This means that any angle in a specific quadrant is +ve acc to 1)
So, now coming to your question, the question is talking about sin, which is +ve in the 1st and 2nd quadrant.
The angle already given to us is in the 1st quadrant, so now we know we will get the same value in the second quadrant in the 2nd quadrant (180-x) or the after 360 (360+x)
Taking -50 to be x
we have the other two angles as,
180-(-50) = 180+50 = 230
360+(-50) = 360-50 = 310
hope that helps, not specifically for this question, but in general.

[idrees]

hey i really need help with this Q.

its killing me! if someone could just explain the dynamics of this q .. how do i go about solving the question. thats all i need .. im really good at mensuration, i have just forgotten how to solve questions regarding rate of flow of water ..

June 2007 p4 Q7

Thanks a LOT!

[Fastal]

hey i really need help with this Q.

its killing me! if someone could just explain the dynamics of this q .. how do i go about solving the question. thats all i need .. im really good at mensuration, i have just forgotten how to solve questions regarding rate of flow of water ..

June 2007 p4 Q7

Thanks a LOT!

the question means that 0.3*1.2*3 m³ flows in 1 minute so 1 hour is 64.8 m³