Mathematics: Post your doubts here!

[Starlight97]

r u sure the answers r correct
i cnt even get the key angle right :O

thats what i was thinking

 

[RoOkaYya G]

h

I just get 70
Haya Ahmed are answers for C correct?

ow u got the 70?

 

[RoOkaYya G]

thats what i was thinking

yeah even with sin inverse 0.5 we cnt get the key angle :/

 

[Starlight97]

h

ow u got the 70?

what u got

 

[Thought blocker]

h

ow u got the 70?

Looking at the domain 0 to 360 no negative answers.
Sin inverse 0.5 = 30 + 180 = 210 / 3 = 70.

 

[Thought blocker]

yeah even with sin inverse 0.5 we cnt get the key angle :/

Did you add 180 Then did you divide it by 3 ?

 

[RoOkaYya G]

Looking at the domain 0 to 360 no negative answers.
Sin inverse 0.5 = 30 + 180 = 210 / 3 = 70.

i forgot to /3 -__-

 

[Thought blocker]

i forgot to /3 -__-

 

[RoOkaYya G]

i got 70 110 190 230 only

 

[RoOkaYya G]

wait!! i got it all

 

[Thought blocker]

wait!! i got it all

Kaisey?

 

[RoOkaYya G]

its 3x means 6 solutions
u do sin inverse 0.5 =30
its negative so 180+30=210 /3 =70
360-30=330 /3 = 110
210+360=570 /3 =190
330+360=690 /3 =230
570+360=930 /3 = 310
690+360=1050 /3 =350

for 1st turn u do by quadrant
for 2nd and 3rd term add 360 for each new set of values obtained
to make answer in ranger for trig always add or subtract 360

 

[Haya Ahmed]

I get all the answers of c except 190 and btw for question a aren't we supposed to add -180 to the answers to be in range ?
Thought blocker RoOkaYya G Starlight97

 

[Haya Ahmed]

Can u

its 3x means 6 solutions
u do sin inverse 0.5 =30
its negative so 180+30=210 /3 =70
360-30=330 /3 = 110
210+360=570 /3 =190
330+360=690 /3 =230
570+360=930 /3 = 310
690+360=1050 /3 =350

for 1st turn u do by quadrant
for 2nd and 3rd term add 360 for each new set of values obtained
to make answer in ranger for trig always add or subtract 360

Explain the 190 part?

 

[RoOkaYya G]

Can u

Explain the 190 part?

the 3x values are as such = 210,330,570,690,930,1050

210 and 330 are obtained by solving the quadrants (180+30 and 360-30)
570 and 690 are obtained by adding 360 to 210 and adding 360 to 330 (this is done for a 2nd turn round the CAST quadrant)
930 and 1050 are obtained by further adding 360 to 570 and 360 to 690 (this is done for a the last i.e the 3rd turn round the CAST quadrant)

then for value of x (divide all the 6 solutions by 3) = 70,110,190,230,310,350

 

[Haya Ahmed]

Guys .. this question .. I'm fine with part (ii) to get the answer but the problem is why in part (i) we didn't cancel the sq root 2 at the denominator as we did in part (ii) please explain how to get both the answers .. or how to change the form of one to the other
THIS IS THE QUESTION

and this is the ANSWER

Thought blocker
ZaqZainab
RoOkaYya G
Rutzaba

 

[Rutzaba]

Guys .. this question .. I'm fine with part (ii) to get the answer but the problem is why in part (i) we didn't cancel the sq root 2 at the denominator as we did in part (ii) please explain how to get both the answers .. or how to change the form of one to the other
THIS IS THE QUESTION

and this is the ANSWER

Thought blocker
ZaqZainab
RoOkaYya G
Rutzaba

and wats ur answer?

 

[ZaqZainab]

Guys .. this question .. I'm fine with part (ii) to get the answer but the problem is why in part (i) we didn't cancel the sq root 2 at the denominator as we did in part (ii) please explain how to get both the answers .. or how to change the form of one to the other
THIS IS THE QUESTION

and this is the ANSWER

Thought blocker
ZaqZainab
RoOkaYya G
Rutzaba

I still did'nt study this part of Alevels

 

[Thought blocker]

Guys .. this question .. I'm fine with part (ii) to get the answer but the problem is why in part (i) we didn't cancel the sq root 2 at the denominator as we did in part (ii) please explain how to get both the answers .. or how to change the form of one to the other
THIS IS THE QUESTION

and this is the ANSWER

Thought blocker
ZaqZainab
RoOkaYya G
Rutzaba

Both part?

 

[Thought blocker]

Guys .. this question .. I'm fine with part (ii) to get the answer but the problem is why in part (i) we didn't cancel the sq root 2 at the denominator as we did in part (ii) please explain how to get both the answers .. or how to change the form of one to the other
THIS IS THE QUESTION

and this is the ANSWER

Thought blocker
ZaqZainab
RoOkaYya G
Rutzaba

Well, here is both the part.
Bit clean up this time
So here it goes,
i)
Use sum and Difference formula Sin (A + B) = Sin(A) x Cos(B) + Sin(B) x Cos(A)
sin(45 + 30) = sin(45)cos(30) + sin(30)cos(45)
= √3 / 2√2 + 1 / 2√2 = (√3 + 1) / 2√2

ii)
Angle B is 105°
AC / sin(B) = AB / sin(C)
AB = 10sin(45) / sin(105)
AB = 10sin(45) / sin(75) --- {Since 105 and 75 are the same distance from 90}
AB = 10/√2 ÷ (√3 + 1) / 2√2
AB = 20 / √3 + 1