well the formula is not very clear ... i am guessing it is X(n)=2*X(n-1)-1/2*X(n-2) ..akay wrote:Please help with this...
In a certain sequence, the term xn is given by the formula xn=2xn-1 – ½ (xn-2) for all n > 2. If x0=3 and x1=2, what is the value of x3 ?
(A) 2.5
(B) 3.125
(C) 4
(D) 5
(E) 6.75
we have X(0)=3 and X(1)= 2 ..
we need X(2) ... so substitute n = 2 in the formula .. and we have X(2) = 2 *X(2-1)-1/2*X(2-2) = 2*X(1)-1/2*X(0).. substituting the value of X(1) and X(0) .. in the formula, we get X(2)=2*2-1/2*3 = 4 - 1.5 = 2.5 ..
for finding X(3) .. substitute n = 3 in the formula and we have X(3)= 2*X(2)-1/2*X(1) = 2*2.5- 1/2*2 = 5 - 1 = 4 ... so the answer is C ..
