C1 and C2 DOUBTS HERE!!!!!

[Weaam]

2008

THANKSS SO MUCHHH! I OWE U BIG TIMEE 

[The Golden Girl =D]

I'l upload the rest later or perhaps tomorrow iA.

[The Golden Girl =D]

I have a doubt and I really need it to be answered today.

C1 book Page : 151 ,Q 10.

the curve C has Equation

y = 8x + x^2 + 9/x

the Points P and Q lie on C and have X-coordinates -3 and 1 respectively

a] find an equation of the chord PQ

b] show that the tangents to Z at the points P and Q are Parallel

the Tangent to C at P and the normal to C at Q intersect at point R(17,2)

D] find QR

E] explain why angle PQR is a right triangle and find the area of triangle PQR.

c and d - I can do them as for the rest , I haven't gotten a single thing correct ,I don't know why =[

[The Golden Girl =D]

Anyone

[The Golden Girl =D]

Another Question.
 
Question No.8 on page 148

Attached.

[Dibss]

the curve C has Equation

y = 8x + x^2 + 9/x

the Points P and Q lie on C and have X-coordinates -3 and 1 respectively

a] find an equation of the chord PQ

b] show that the tangents to Z at the points P and Q are Parallel

for a) find coords of p by substituting x=-3 in the equation
y=-24+9-3
y=-18
P(-3,-18)

for q, put x=1 in the eqtn.
y=8+1+9
y=18
Q(1,18)

To find eq of PQ, find grad
m = -36/-4
=9
Eq PQ => (y-18)/(x-1)=9
Solve

b) Find dy/dx
8+2x-9x^-2
to find grad at P, put in x=-3
to find grad at Q put in x=1
You should get the same answer for both. Gradients are same therefore, parallel.

I'm in school right now, but I'll try and get back to you with the rest later. (:

[The Golden Girl =D]

okay thx =]

[Dibss]

Okay a and b you understand now. c and d you alredy knew. Leaves us with e.

E] explain why angle PQR is a right triangle and find the area of triangle PQR.

Eq of PQ was y=9x+9 therefore grad = 9
Calculate grad of QR => you get -1
Calculate grad of PR => you get 1
Since the product of gradients of QR and PR is -1 it proves they are perpendicular to each other. Therefore PQR is a right-angled triangle.

(:

[Dibss]

Another Question.
 
Question No.8 on page 148

a=400
d= x or 30

a) U₁₀= a + (n-1)d
=400+9(30)
=670

b)S₁₀= n/2 [2a + (n-1)d]
10/2 [2 x 400 + 9 x 30]
=5350

c)Equate S₁₀ formula to 6000
10/2 [800 +9x] = 6000
800+9x=1200
x=44.4
Obviously he can't produce 44.4 cars every year so to reach the target, the minimum he must produce is 45.

Clear? (:

[The Golden Girl =D]

clear

[Dibss]

one se can , you tell me how to find the AREA for PQR ?

Find length of PR and then the length of QR.
^use formula square root of [(x1-x2)²+ (y1-y2)²)
then use area = 1/2 x b x h

Or you can use the other method that involves listing coordinates and the criss cross lines (I don't know how to explain it by typing )

clear

I saw your previous post ;] Tried to quote it and then saw this. I'm glad you got it. (:

[The Golden Girl =D]

I got it

[Weaam]

I need the mark scheme for June 2009, i cant find it anywhere ! 

[Malak]

I need the mark scheme for June 2009, i cant find it anywhere ! 

[Dibss]

^Thanks for helping her, angel.
+Rep. (: