Proving trig identities -- Is the method related to the unit circle?

[Mark44]

Post #47:

Ok I will say thank you less in precalculus forums.

Post #50:

Thank you for your replies @malawi_glenn !
<snip>
Many thanks!

Less $\ne$ more -- just saying.

 

[kuruman]

Thank you for your replies @malawi_glenn !

$|z| = r^2[\cos^2\theta + \sin^2\theta] = r^2[1] = r^2$

Many thanks!

The equation should begin with $|z|^2=\dots$

 

[member 731016]

The equation should begin with $|z|^2=\dots$

True, thanks for pointing that out @kuruman!

 

[chwala]

What do you mean by "Thanks"?

I intended that you apply that to $\displaystyle \cos(\theta)+i\sin(\theta)$ and show that its Modulus is indeed $1$ .

Math is a not a spectator sport. You must practice and do, not just watch and cheer.

@SammyS you made my day! I'll pass this to my students.

' Math is a not a spectator sport. You must practice and do, not just watch and cheer".

Nice one mate.

 

[chwala]

True, thanks for pointing that out @kuruman!

@ChiralSuperfields i would suggest on a light note that you avoid the many thanks remarks in your posts and instead stick to the material/work at hand. That is how you will gain respect and momentum in the subject. Get down to work! Cheers mate.