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

    10
    ReputationRep:
    can someone help me with this, i dont understand what sin(180-theta) =sintheta means also i dont understand how to express for example sin(theta) in terms of sin(theta)

    please someone help me and explain it to me
    Offline

    20
    ReputationRep:
    see what happens if you put different angles for theta in sin( 180 - theta ) and sin ( theta )
    • Thread Starter
    Offline

    10
    ReputationRep:
    (Original post by the bear)
    see what happens if you put different angles for theta in sin( 180 - theta ) and sin ( theta )



    E.g if i put sin(180-46) the answer is the same as sin (46)

    but what does express in term of sin(theta) means, for example sin(-theta)
    Offline

    20
    ReputationRep:
    (Original post by Mr revision)
    E.g if i put sin(180-46) the answer is the same as sin (46)

    but what does express in term of sin(theta) means, for example sin(-theta)
    so we can say that sin( 180 - Θ ) can be written as sin ( Θ )

    we have expressed sin( 180 - Θ ) in terms of sin ( Θ )
    Offline

    21
    ReputationRep:
    (Original post by Mr revision)
    can someone help me with this, i dont understand what sin(180-theta) =sintheta means also i dont understand how to express for example sin(theta) in terms of sin(theta)

    please someone help me and explain it to me
    Draw a graph of sin\theta. Because it is periodic and symmetric (about certain values), you should be able to see why the above is true.
    • Thread Starter
    Offline

    10
    ReputationRep:
    (Original post by the bear)
    so we can say that sin( 180 - Θ ) can be written as sin ( Θ )

    we have expressed sin( 180 - Θ ) in terms of sin ( Θ )


    sorry to be bothering you but how will you work out for example if the question says given that theta is an acute angle measured in degrees, express in terms of sin(theta) sin(-theta)

    please help me and thanks also this is not my homework by the way, its independent work
    Offline

    21
    ReputationRep:
    (Original post by RogerOxon)
    Draw a graph of sin\theta. Because it is periodic and symmetric (about certain values), you should be able to see why the above is true.
    From the graph, you should see:

    sin(180-\theta)=-sin(-\theta), as you're translating the \theta=0 point from where the curve goes down to where it goes up, so need to negate it.

    Then:
    -sin(-\theta)=sin\theta should be obvious from the graph.
    Offline

    20
    ReputationRep:
    (Original post by Mr revision)
    sorry to be bothering you but how will you work out for example if the question says given that theta is an acute angle measured in degrees, express in terms of sin(theta) sin(-theta)

    please help me and thanks also this is not my homework by the way, its independent work
    just look up sin 30, sin -30

    sin 56, sin -56

    you should spot a pattern ?
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Will you be richer or poorer than your parents?
    Help with your A-levels

    All the essentials

    The adventure begins mug

    Student life: what to expect

    What it's really like going to uni

    Rosette

    Essay expert

    Learn to write like a pro with our ultimate essay guide.

    Uni match

    Uni match

    Our tool will help you find the perfect course for you

    Study planner

    Create a study plan

    Get your head around what you need to do and when with the study planner tool.

    Study planner

    Resources by subject

    Everything from mind maps to class notes.

    Hands typing

    Degrees without fees

    Discover more about degree-level apprenticeships.

    A student doing homework

    Study tips from A* students

    Students who got top grades in their A-levels share their secrets

    Study help links and info

    Can you help? Study help unanswered threadsRules and posting guidelines

    Sponsored content:

    HEAR

    HEAR

    Find out how a Higher Education Achievement Report can help you prove your achievements.

    Groups associated with this forum:

    View associated groups
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • 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.