Real SAT II Subject test Math 2 help

Test Preparation SAT Subject Test Preparation
1

<p>can anyone explain problem 34, page 179 in the blue CB Real SAT Subj Tests?</p>

<p>If x(subzero) = 0 and x(sub n+1) = sqrt(6 +x(sub n)), then x (sub3) = ?</p>

<p>A. 2.449
B. 2.907
C. 2.984
D. 2.997
E. 3.162</p>

2

<p>This is going to look messed up in computer notation but I'll try.</p>

<p>You know that x(sub3) = x(sub2+1) = sqrt(6 +x(sub2)).</p>

<p>x(sub2) = x(sub1+1) = sqrt(6 +x(sub1)).</p>

<p>x(sub1) = x(sub0+1) = sqrt(6 +x(sub0)) = sqrt(6).</p>

<p>When you do all the substitutions, you should get x(sub3) = sqrt(6+sqrt((6+sqrt(6))) = 2.984</p>

3

<p>It's just a matter of substituting in, like dagr8est said...really not that hard.</p>

4

<p>is that calculus?
im currently taking precalc and it looks like heiroglyphics to me...</p>

5

<p>Not calculus at all...simple algebra. You just have to know how the subscript notation works.</p>

6

<p>If it helps, you can think of it as a function, defined as
x(n+1) = sqrt(6 + x(n))
with x(0) = 0</p>

<p>You can program this into Excel, if it helps. Type 0 in (say) cell A1 in a worksheet, then type =SQRT(6+A1) into cell A2. Copy the formula in cell A2 into A3,A4,A5,... . Cell A1 shows x(0), and cell An will show x(n-1)</p>