Mathematics: Post your doubts here!

[RoOkaYya G]

perhaps, you are v genius

im not trust me

 

[RoOkaYya G]

well tbh i dont know how to solve it ^^
What chapter is it from?

How to solve it?

its simple logic

the diameter of the circle is 5 so radius is 2.5
hence the hypotenus is 2.5
the adjacent side is (2.5-1) =1.5
using pythagoras theorem :
2.5^2 = 1.5^2 = x^2
x =2

 

[Emma23]

How do you do question 7 part 3?

 

[RoOkaYya G]

How do you do question 7 part 3?

for least value of arg z means the smallest angle possible
ths means the tangent to the cricle must be such tht it makes the least possible angle
so u draw the tangent from starting point O to where it makes the least possible angle with the circle
u calculate modulus of z by assuming the tangent the hypotenus of a right angled triangle.
use pythagoras theorem or sin rule if u want.
the O will be the radius of the circle
the H will the moduls of z
use sin rule. its easier.

 

[Haya Ahmed]

take

ln on both side
3.9 lnx=3.2 ln 11x

simplifying the 3.2 ln11x part :
3.2 lnx+ ln11

3.9lnx= 3.2 lnx+ln11
3.9lnx -3.2 lnx =ln11
ln x( 3.9-3.2) = ln 11
lnx = ln11 / (3.9-3.2)

x= ln inverse [ln11 / (3.9-3.2)]

Is there anything called ln inverse ?!

 

[Haya Ahmed]

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_s11_qp_21.pdf

Q8 (iii) the greatest and leastvalue is 60 and I got it .. but what about 8 ? from where are we supposed to get it

 

[RoOkaYya G]

Is there anything called ln inverse ?!

-_______- it become the e in calculator

 

[RoOkaYya G]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s11_qp_21.pdf

Q8 (iii) the greatest and leastvalue is 60 and I got it .. but what about 8 ? from where are we supposed to get it

wait ill see to it

 

[Haya Ahmed]

-_______- it become the e in calculator

I did it in this way is it right?.. sorry for the sloppy handwriting !!

 

[RoOkaYya G]

I did it in this way is it right?.. sorry for the sloppy handwriting !!

y u complicate ur life?
u send 0.7 down ln 11 instead of sending ln x
itll be easier.
its good though.
but u might make mistake in typing root 0.7 so avoid
n do ln inverse which is e power (ln 11 / 0.7)

 

[RoOkaYya G]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s11_qp_21.pdf

Q8 (iii) the greatest and leastvalue is 60 and I got it .. but what about 8 ? from where are we supposed to get it

btw greatest value is 60 n least is 8
u got greatest right?

 

[Haya Ahmed]

btw greatest value is 60 n least is 8
u got greatest right?

aren't both 60 ? .. because sqr root 26 x 1/-1 and then we square the ans we get 52 because -ve is canceled in squaring and +8 is 60 which is for both ..?!

 

[RoOkaYya G]

aren't both 60 ? .. because sqr root 26 x 1/-1 and then we square the ans we get 52 because -ve is canceled in squaring and +8 is 60 which is for both ..?!

whts the logic then if both is 60? greatest nsmallest cnt be same value!! it can but only with opposite signs -_______-

 

[Haya Ahmed]

whts the logic then if both is 60? greatest nsmallest cnt be same value!! it can but only with opposite signs -_______-

Ohhh .. I got the idea now !! ... so -1 and 1 have the highest values but 0 have the lowest value ?! right ? .. cuz -1<cos/sin<1 and 0 is included in the range .. am I rightt !!

 

[RoOkaYya G]

Ohhh .. I got the idea now !! ... so -1 and 1 have the highest values but 0 have the lowest value ?! right ? .. cuz -1<cos/sin<1 and 0 is included in the range .. am I rightt !!

yes!!! finally!!!
else i thought uve sign a contract to drive me crazy hihi

 

[Haya Ahmed]

yes!!! finally!!!
else i thought uve sign a contract to drive me crazy hihi

LOOL .. thanks .. I'm sorry ... maths made me crazy today .. solving maths since 12 hours continuously

 

[RoOkaYya G]

LOOL .. thanks .. I'm sorry ... maths made me crazy today .. solving maths since 12 hours continuously

haha ^_^ doesnt matter
uve any other doubts?

 

[Wolfgangs]

How to solve trigonometrical equations within the range of -180<x<180? Is there a specific rule for it? For example, tan x = 45 and sin 2x = 2 sin x

 

[RoOkaYya G]

How to solve trigonometrical equations within the range of -180<x<180? Is there a specific rule for it? For example, tan x = 45 and sin 2x = 2 sin x

solve the trig normally.
to make the answer in range...always add or subtract 360 from it.
if the angle is x there shld be 2 solutions...but if despite adding or subtracting 360..one answer doesnt fall in range...give both answers...BUT rewrite the real answer which is in range for example.... x =45 and x =190
but the quest range is 0<x<180
so x = 45 for 0<x<180 <---------WRITE LIKE THIS

 

[Thought blocker]

Any doubts left?