View Full Version : Trigonometry proofs
mwilt
Mar 4, 2009, 03:04 PM
how do you prove that
tanx+coty / tanxcoty = tany+cotx
galactus
Mar 4, 2009, 03:50 PM
\frac{tan(x)+cot(y)}{tan(x)cot(y)}
This only requires about one step.
Expand it out and look at the cancellations.
\frac{tan(x)}{tan(x)cot(y)}+\frac{cot(y)}{tan(x)co t(y)}
See it?
mwilt
Mar 4, 2009, 08:52 PM
Thank you! I get it now!
cazey
Jun 9, 2009, 07:01 PM
how do I prove that sin20=x/8?
Perito
Jun 9, 2009, 07:42 PM
If I read your question correctly,
sin(20)=\frac {x}{8} ?
That looks more like an equation than a proof.
x=8 sin(20) \approx 2.736