Join TSR now and get all your revision questions answeredSign up now

Trig functions powers

    • Thread Starter
    Offline

    0
    ReputationRep:
    I was wondering why sin^2(x) = (sin(x))^2 ​​but sin^-1(x) ≠ (sin(x))^-1 ?
    Offline

    3
    ReputationRep:
    It's really just because of unfortunate notation.

    sin-1(x) the way you know it means "the inverse of sine" meaning that if sin(a) = b then sin-1(b) = a.

    unfortunately this clashes with when we say sin^2(x) meaning sin(x)^2

    To avoid this you can use arcsin, arccos and arctan (short for arcsine, arccosine and arctangent) meaning "the inverse of sine..." etc

    To write 1/sinx I would either write just that (1/sinx) or sin(x)^-1 to avoid confusion.
 
 
 
Poll
Do you have exam superstitions?
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.