Mathematics: Post your doubts here!

[RoOkaYya G]

ohhh!!!!!!! it said show!!!!!!!!
sorryyy i dint notice tht
i jst did the (ii) then

Wait ill do it Haya Ahmed

 

[Haya Ahmed]

Haya Ahmed
taking the horizontal section of the corridor :
W = xcos theta + b sin theta
adjacent =cos theta * hypotenus

=xcos theta
opposite of smaller triangle = sin theta * b

=bsin theta

w= xcos theta + bsin theta (HENCE SHOWN)

the side W = the adjacent side of the line AD (when taken in a triangle) + the opposite side of angle theta
so :
calculating the the adjacent side of the line AD (when taken in a triangle) :
the adjacent side of the line AD (when taken in a triangle)
cos theta =adjacent/ hypotenus
adjacent=cos theta * hypotenus =cos theta * b
=bcos theta

calculating the opposite side of angle theta :
sin theta = opposite/ hypotenus
hypotenus = length a of rectangle - part x of side CD
= a-x
sin theta = opposite / (a-x)
opposite = (a-x) *sin theta


HENCE , w= b cos theta + (a-x) sin theta <--------- ANSWER

ii)
im unable to do ths part :S sorry

iii)
replace 45 - phi in the equation in part (ii) which is already given
use compound angle to expand and reach the solution asked there

iv) replace the values given in the equation given in part (iii)
solve for theta

ina hurry so plz manage
if u still dont get it then tell me for part iii and iv
ill do it stepwise

for (ii) im missing smethng i thnk. ill try it again later if u still dont get it. try ask someone else

well I'm lost here too .. which one is adjacent which is hypotenus ?! ... for the 1st part

 

[RoOkaYya G]

well I'm lost here too .. which one is adjacent which is hypotenus ?! ... for the 1st part

try figure out a right angle triangle with the 2 sides already given na

 

[RoOkaYya G]

well I'm lost here too .. which one is adjacent which is hypotenus ?! ... for the 1st part

btw for the 45 ...im unable to derive it from tan(A-B)

the B is obviously the theta. the A is the whole angle (the theta + the angle beside it)
expanding the tan formula...i tried to replace n all..but im unable to get tht
im ina hurry too...try ask smeone else...
if not..
ill re try it later.

 

[Haya Ahmed]

try figure out a right angle triangle with the 2 sides already given na

I still didn't get it , I'm sorry I'm disturbing you but if you can just use paint to show me the triangles where u used them to get xcos theta and bsin theta !

 

[RoOkaYya G]

Haya Ahmed

 

[Haya Ahmed]

http://papers.xtremepapers.com/CIE/...AS Level/Mathematics (9709)/9709_w04_qp_2.pdf
Q2 how to do this question

 

[RoOkaYya G]

take ln on both sides

yln3 = (x+2)ln 4

y ln3 = xln4 + 2ln 4

y = (ln4/ln3) x +2ln4 ------------> in form of y=mx + c which is the general form of equation of line. hence its a straight line

gradient = m = ln4/ln3
Haya Ahmed

 

[RoOkaYya G]

take

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w04_qp_2.pdf
Q2 how to do this question

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)]

 

[Thought blocker]

RoOkaYya G I thought there will be piles of doubts when I come back. But, thanks to you.

 

[RoOkaYya G]

RoOkaYya G I thought there will be piles of doubts when I come back. But, thanks to you.

pleasure

 

[***amd***]

A semicircle is shown.
Find the value of x.
Just sharing a tricky Q.

 

[RoOkaYya G]

Find the value of x.
Just sharing a tricky Q.

r u kidding around?

 

[***amd***]

r u kidding around?

what makes you think that way?

 

[RoOkaYya G]

what makes you think that way?

answer is 2
even a kid would do tht y u say tricky?

 

[asadalam]

answer is 2
even a kid would do tht y u say tricky?

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

 

[***amd***]

answer is 2
even a kid would do tht y u say tricky?

perhaps, you are v genius

 

[***amd***]

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

that circles wala chap in o levels

 

[asadalam]

that circles wala chap in o levels

How to solve it?

 

[RoOkaYya G]

that circles wala chap in o levels

circle wala chap
circular measure