Here's a snippet from the working in a trigonometry textbook. I'm confused about the second line:
Am I correct in interpreting from this that: $1 - \sin^2 \theta \equiv (1 - \sin\theta)^2$ ?
Until now I had thought that $1 - \sin^2 \theta \equiv 1 - (\sin\theta)^2$
Which is correct?
Thanks!