<p>So my math teacher, who is a Columbia finance graduate, told us he had a difficult math problem, that he believes would be a good SAT question. I tried for a while, but got nowhere close to the answer...which doesn't really mean anything because I'm awful at math.</p>
<p>Anyway, I normally wouldn't care, but I'm curious as to how to do this now, especially considering the SAT is this Saturday.</p>
<p>In the equation y= a sin(bx+c)+d
** a=2.33
b=0.57
c=2.57
d=14.98</p>
<p>Find a cosine model for these values of sine**
In other words, rewrite the equation in terms of cosine as opposed to sine. </p>
<p>Can anyone tell me how to do this, or give me an explanation? I doubt there will be much trig on the SAT, but I would like to know.</p>
<p>Thank you for your time!</p>
<p>There is never or has never been any formal form of trig on the SAT. On some very rare occasions it may come in handy but it is never necessary. I scored an 800 on the math in march and am confident that there will be no trig. on it so you don’t have to worry. Goodluck!</p>
<p>You wouldn’t change a or d at all. I am pretty sure the only thing you would change is c. You would have to move it to the left or right pi/2, so c + or - pi/2. I don’t remember what b’s effect on the sine curve, but I am pretty sure if b=1 what I just said holds true.</p>
<p>Really easy</p>
<p>sin x = cos (x - pi/2)</p>
<p>so just stick a - pi/2 at the end of it</p>
<p>and btw this will never be on the SAT I math</p>
<p>I don’t think ‘a’ changes. I’m not really doing it for the SATs anymore, but he will be giving us a similar problem on a test Monday. Here is what I got so far. If someone could tell me if on I’m on the right track.</p>
<p>sin(x) = cos ((pi/2)-x) = cos (1.57-x)</p>
<p>y = 2.33 sin (0.57x + 2.57) + 14.98
= 2.33 cos (1.57 - (0.57x + 2.57)) + 14.98
= 2.33 cos (1.57 - 0.57x - 2.57) + 14.98
= 2.33 cos (-1 - 0.57x) + 14.98</p>
<p>= 2.33 cos (-0.57x -1) + 14.98</p>
<p>Is this right?? I know there’s a lot of people on here that can do this with little to no effort, but I don’t have that privilege :(</p>
<p>Graph both equations on your calculator to check the answer.</p>