limits ? (1 Viewer)

[purplemoon]

please help:

lim sin(pi-x)/x
x-->o

The answer is 1, but i'm unsure of how to get that

thanks

 

[seanieg89]

Use that sin(pi-x)=sin(x).

 

[purplemoon]

thanks, but why is sin(pi-x)=sin(x) ?

 

[Shadowdude]

Draw a picture.

 

[seanieg89]

Perhaps the easiest way to convince yourself of this is by expanding the LHS using your compound angle formulae for sin.

I recommend getting a good feel for the symmetry properties of the trig functions though, personally I just visualise the unit circle.

 

[purplemoon]

Thanks, i had not been exposed to the unit circle, but it makes sense now. Thankyou