Question

A sequence U1, U2,U3...... is defined by the relation Un +1 = 2Un +5. if U1 =2, find U1​

Answer 1

Correct question:

a sequence U1, U2,U3...... is defined by the relation $U_{n +1} = 2U_n +5$. if U1 =2, find U2​ and U3

Answer:

U2 = 9

U3 = 23

Step-by-step explanation:

Given sequence;

$U_{n +1} = 2U_n +5$

U1 = 2

U2 = ?

$U_{n +1} = 2U_n +5\\\\U_2 = 2(U_1) + 5\\\\U_2 = 2(2) + 5\\\\U_2 = 4 + 5\\\\U_2 = 9$

Solving for U3;

$U_3 = 2(U_2) + 5\\\\U_3 = 2(9) + 5\\\\U_3 = 18 + 5\\\\U_3 = 23$