<p>I'm an 8th grader taking the ACT in Feb and the only questions I missed on the practice test were trig ones (I got a 34). What would be the most applicable and useful trig knowledge for the ACT math, even though there are not at alot of them?</p>
<p>A few trig identities to remember:</p>
<p>sin^2(x) + cos^2(x) = 1 (Using pythag)
sin(x)/cos(x) = tan(x)
sin(x+y) = sin(x)cos(y)+sin(y)cos(x)
cos(x+y) = cos(x)cos(y)-sin(x)sin(y)</p>
<p>And a bunch of others. Just search trigonometry identities on google and you should get a bunch of results.</p>
<p>On another note, you have loads of time to improve, so there's nothing to worry about... If you really want to put some time into trigonometry then you might want to look up the unit circle as it will help you a lot in trigonometry (both for the ACT and in the future)...</p>
<p>holy crap... 8th grader getting a 34 in math... dang.</p>
<p>:D I just got 30's in the rest of the subjects :P</p>
<p>But on a different note, is there any deathly important trig stuff I sould know other than identities?</p>
<p>of the identities mentioned above...i really think the only (or at the least, MOST) useful is
sinx/cosx=tanx</p>
<p>Do you know SohCahToa? (as i call it)...like the basics?</p>
<p>sinx=opp/hyp
cosx=adj/hyp
tan=opp/adj</p>
<p>Oh, and know these:</p>
<p>1/sinx=cscx=hyp/opp
1/cosx=secx=hyp/adj
1/tanx=cotx=adj/opp</p>
<p>=)</p>
<p>some sort of child prodigy???</p>
<p>yeah if you get a 34 on math as an 8th grader, just hold off a bit. you will for sure get a 36 on it once you've actually learned trig. no reason to rush because it can be a confusing topic. memorizing formulas and identities in trig isnt really a good thing if you cant relate it all back to the unit circle and understand why they exist. Basically, once you learn it for real, you'll be fine.</p>