Mathematics: Post your doubts here!

[Ebrahim12]

Can anybody help with its (ii) part? It is from M/J 2012 v33 and the answer is 100/e.

View attachment 64388

Was your answer to the first part y = 70e^[e^(-3t) - 1] ?

As t goes to infinity,

e^-3t tends to zero​

thus,

y tends to 70e^[0 - 1] = 70e^-1​

so we have:

yFinal = 70e^-1
yStart = 70 (from main question)

p = (yFinal/yStart)*100
p = 100e^-1​

 

[EXPERTS]

help required !!!!!!! in part b

 

[A*****]

View attachment 64419View attachment 64420
help required !!!!!!!

Which part?

 

[A*****]

Was your answer to the first part y = 70e^[e^(-3t) - 1] ?

As t goes to infinity,

e^-3t tends to zero​

thus,

y tends to 70e^[0 - 1] = 70e^-1​

so we have:

yFinal = 70e^-1
yStart = 70 (from main question)

p = (yFinal/yStart)*100
p = 100e^-1​

Thanx alot!!

 

[A*****]

How are the values of α and β calculated in the last part? Anyone plz help.....

 

[A*****]

in part (b)

For b (i), AC is the diameter of the circle so APC will be the angle opposite to the diameter, i.e. angle in a semicircle=90°
Or you can think of it by the other rule...ABCP is a quadrilateral with its vertices touching the circumference so opposite angles will be equal. Hence, angle APC=angle ABC

In b (ii), angle APB is subtended by the chord AB, whereas angle BPC by the chord BC.Angles subtended by chords of equal length are equal and since AB=BC, the stated angles are equal.

In b (iii) (a) APC=90 and APB and BPC are equal, so APB=90/2=45
In b(iii) (b), angle CPD is also subtended by an equal chord so it will also equal angle APB i.e. 45. Hence, APD= 45+45+45=135

For b(iv) see the diagram


So angle PDC=90+8=98

 

[Ebrahim12]

View attachment 64421

How are the values of α and β calculated in the last part? Anyone plz help.....

What are the answers? Is alpha = 1.23?

 

[A*****]

What are the answers? Is alpha = 1.23?

That's 0.424

 

[Ebrahim12]

That's 0.424

This makes sense?

 

[Lemniscates]

Can anyone help me? I'm in A2 and it's just 4 months left my subjects are Phy, Maths and C.S. Any hope ?

Depends on how well are you doing right now. You can inbox me for discussing about this topic.

 

[Lemniscates]

This makes sense?
View attachment 64424

Perfect.

 

[EXPERTS]

need help in part b and c

 

[Ebrahim12]

View attachment 64427


need help in part b and c

b)
Having two sides be the same makes it an isosceles triangle
360 = 66 + 2x
C)
ADE and EFC are equal (alternate angles)
ECF you already have
FEC and AED are equal

 

[A*****]

View attachment 64427


need help in part b and c

Better to post in O level thread

 

[EXPERTS]

Better to post in O level thread

dont be angry sis

 

[EXPERTS]

b)
Having two sides be the same makes it an isosceles triangle
360 = 66 + 2x
C)
ADE and EFC are equal (alternate angles)
ECF you already have
FEC and AED are equal

thanks man

 

[A*****]

dont be angry sis

Lol do u think that smile meant I'm angry? Come on!!

 

[A*****]

Lol do u think that smile meant I'm angry? Come on!!

And I just said u do so ,so that more ppl would be available there to answer ur questions...just for ur benifit

 

[A*****]

i never thought about it i just doubted

I hope ur doubts are cleared by now

 

[A*****]

AHHH !!!!! this smile seems good