Join TSR now and get all your revision questions answeredSign up now
    • Thread Starter
    Offline

    2
    ReputationRep:
    Could someone explain step by step how to do this?

    In triangle ABC, AB = Xcm, BC = (4 - X) cm, angle BAC = Y and angle BCA = 30 degrees. Given that sin Y degrees = 1/root 2, show that X = 4 (root 2 - 1)


    Posted from TSR Mobile
    Offline

    17
    ReputationRep:
    (Original post by JodieW)
    Could someone explain step by step how to do this?

    In triangle ABC, AB = Xcm, BC = (4 - X) cm, angle BAC = Y and angle BCA = 30 degrees. Given that sin Y degrees = 1/root 2, show that X = 4 (root 2 - 1)


    Posted from TSR Mobile
    Step-by-step solutions are not permitted on the maths forum - you should post some working so that hints can be given.

    If you can't see where to start, think about the sine rule.
    Offline

    0
    ReputationRep:
    (Original post by JodieW)
    Could someone explain step by step how to do this?

    In triangle ABC, AB = Xcm, BC = (4 - X) cm, angle BAC = Y and angle BCA = 30 degrees. Given that sin Y degrees = 1/root 2, show that X = 4 (root 2 - 1)


    Posted from TSR Mobile
    Draw a triangle then look at your rules of trig from the chapter you learned
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by Farhan.Hanif93)
    Step-by-step solutions are not permitted on the maths forum - you should post some working so that hints can be given.

    If you can't see where to start, think about the sine rule.
    Name:  ImageUploadedByStudent Room1363966912.227643.jpg
Views: 76
Size:  182.5 KB

    This is what I've done so far. I don't know if it's right :/


    Posted from TSR Mobile
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by Robbie242)
    Draw a triangle then look at your rules of trig from the chapter you learned
    I've done this so far but I just don't know how to continue to get X = 4(root 2 - 1)



    Posted from TSR Mobile
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by JodieW)
    I've done this so far but I just don't know how to continue to get X = 4(root 2 - 1)



    Posted from TSR Mobile
    Name:  ImageUploadedByStudent Room1363967022.119163.jpg
Views: 46
Size:  182.5 KB


    Posted from TSR Mobile
    Offline

    0
    ReputationRep:
    (Original post by JodieW)
    Name:  ImageUploadedByStudent Room1363966912.227643.jpg
Views: 76
Size:  182.5 KB

    This is what I've done so far. I don't know if it's right :/


    Posted from TSR Mobile
    Rationalise the denominator and then bring all X's to one side and factorise leaving X outside. Then divide through by your factorisation and then rearrange some more
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by Robbie242)
    Rationalise the denominator and then bring all X's to one side and factorise leaving X outside. Then divide through by your factorisation and then rearrange some more
    Name:  ImageUploadedByStudent Room1363967543.500890.jpg
Views: 67
Size:  193.3 KB

    Is this correct so far?


    Posted from TSR Mobile
    Offline

    0
    ReputationRep:
    (Original post by JodieW)
    Name:  ImageUploadedByStudent Room1363967543.500890.jpg
Views: 67
Size:  193.3 KB

    Is this correct so far?


    Posted from TSR Mobile
    You times is by root 2 but in the end you'd still get the same product, so yeah divide through by 2, and then rearrange to have all X's on one side, then factorise and divide through by the bracket; from this point on you type it into your calculator rather then going for another round of rationalising
    • Thread Starter
    Offline

    2
    ReputationRep:
    (Original post by Robbie242)
    You times is by root 2 but in the end you'd still get the same product, so yeah divide through by 2, and then rearrange to have all X's on one side, then factorise and divide through by the bracket; from this point on you take type it into your calculator rather then going for another round of rationalising
    I've done it now, thank you I'm so stupid ._.


    Posted from TSR Mobile
 
 
 
Poll
Which web browser do you use?
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.