I'm having trouble in Khan Academy trigonometry where there are two steps, that aren't a sequence of algebraic manipulations. I get immersed in the second step, and give that as the answer -- forgetting to apply the first step.
For example, unit circle quadrants for $\cos$ and $\sin$:
the quadrant of angle $\theta$ indicates the signs of $\sin \theta$ and $\cos \theta$.
given $\cos \theta$, work out $\sin \theta$, using Pythagoras.
I forget to apply the correct sign.
I also keep makng silly typos, even though I know how to do it. In copying my answer from paper to the site, I omit $\pi$, I omit a negative sign. In my calculations, I use the opposite instead of the hypotenuse.
When I was in high school, I would have dismissed these errors as trivial, and the important thing was understanding. But as an adult, I feel my problem is an inability to handle complexity - even at this very mild level. It's important to be able to get the right answer; to have confidence in mathematics. I also have trouble with complexity in programming. Maybe learning a skill here for trig, will also help there...
How can I improve at handling the (mild) complexity of trig?
PS: some complicating factors: I'm tired; trying to rush through it; doing it on a small smartphone screen; KA often crashes; using google for calculations (which silently accepts mismatched parentheses).