Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    12
    ReputationRep:
    I was doing some revision homework and i came across these trig 'cast diagram' questions:

    4sin(x+20)=1

    5cos(x-15)+1=0

    2sin(x+35)= 1.2

    and I managed to get answers for them like the remainder of the page...but these have very strange answers at the back.

    I would appreciate if someone could solve them so i can see whether i got something similar.

    Thanks a bunch!!!
    Offline

    1
    ReputationRep:
    Wolfram Alpha is definitely your friend for things like this.
    Offline

    2
    ReputationRep:
    (Original post by tinababy)
    I was doing some revision homework and i came across these trig 'cast diagram' questions:

    4sin(x+20)=1

    5cos(x-15)+1=0

    2sin(x+35)= 1.2

    and I managed to get answers for them like the remainder of the page...but these have very strange (i think they're just plain wrong) answers at the back.

    I would appreciate if someone could solve them so i can see whether i got something similar.

    Thanks a bunch!!!
    Would you be able to post a picture of the actual original questions?
    • Thread Starter
    Offline

    12
    ReputationRep:
    (Original post by greenladybird)
    Would you be able to post a picture of the actual original questions?
    This is it.
    Thanks!
    Attached Images
     
    • Thread Starter
    Offline

    12
    ReputationRep:
    (Original post by greenladybird)
    Would you be able to post a picture of the actual original questions?
    This is it. The last three .... h, i, j.
    Thanks
    Offline

    2
    ReputationRep:
    (Original post by tinababy)
    This is it.
    Thanks!
    Just doing it quickly,
    h) x = 145.5
    i) x = 116.5, x = 273.5
    j) x = 108.1, x = 1.9

    That's what I got, what are the answers in the book?
    • Thread Starter
    Offline

    12
    ReputationRep:
    (Original post by greenladybird)
    Just doing it quickly,
    h) x = 145.5
    i) x = 116.5, x = 273.5
    j) x = 108.1, x = 1.9

    That's what I got, what are the answers in the book?

    That's it! For h) is it also 354.5?
    But I'm not sure where I am going so spectacularly wrong though. Would it too much of a hassle if I asked you how to did it?

    Thanks a lot!
    Offline

    2
    ReputationRep:
    (Original post by tinababy)
    That's it! For h) is it also 354.5?
    But I'm not sure where I am going so spectacularly wrong though. Would it too much of a hassle if I asked you how to did it?

    Thanks a lot!
    For h I think there must be only one solution, the other value for 'x' is less than 0.
    I'll try uploading a picture for my working once I've written it out, i'll either post it tonight or tomorrow for you
    Do you want to post your own working, it could just be an error in your working perhaps?

    Edit;
    Here's the working for h)
    Attached Images
     
    • Thread Starter
    Offline

    12
    ReputationRep:
    (Original post by greenladybird)
    For h I think there must be only one solution, the other value for 'x' is less than 0.
    I'll try uploading a picture for my working once I've written it out, i'll either post it tonight or tomorrow for you
    Do you want to post your own working, it could just be an error in your working perhaps?

    Edit;
    Here's the working for h)
    Thank you very much, I get it now! I got up to -5.5 but then I messed it up.
 
 
 
Poll
Do you agree with the PM's proposal to cut tuition fees for some courses?
Applying to university

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

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