Question

Trying to find the equation for the pattern 5, 11, 18, 26, 35, 45​

Answer 1

Answer:

Step-by-step explanation:

$u_{n+1}=u_n+n+5\\\Longrightarrow\ u_{n+2}=u_{n+1}+(n+1)+5\\u_{n+2}-u_{n+1}=u_{n+1}+n+1+5-u_n-n-5\\u_{n+2}=2u_{n+1}-u_n+1\\u_{n+3}=2u_{n+2}-u_{n+1}+1\\\\u_{n+3}-u_{n+2}=2u_{n+2}-u_{n+1}+1 -2u_{n+1}+u_n-1\\\\u_{n+3}-3u_{n+2}+3u_{n+1}-u_n=0\\\\\\Equation\ caract\' eristique:\\r^3-3r^2+3r-1=0\\(r-1)^3=0\\\\\boxed{u_n=a+b*n+c*t^2}\\\\u_1=5\\u_2=11\\u_3=18\\u_4=a+4*b+16*c=26\\u_5=a+5*b+25*c=35\\u_6=a+6*b+36*c=45$

a=0

b=9/2

c=1/2

Proof:

n=1 ==> u_1=1/2*(9+1)=5

n=2 ==> u_2=2/2*(9+2)=11

n=3 ==> u_3=3/2*(9+3)=18

n=4 ==> u_=4/2*(9+4)=26

n=5 ==> 5/2*(9+5)=35

n=6 ==> 6/2*(9+6)=45

...

Download xls

Answer 2

Answer: i have found one that calculates differences when given a sigma with a sigma rule, you could adjust the formula for patterns, if you create a sigma equation and then apply the formulas and then make up a pattern that falls within it, knowing the connection is they go up in the same numbers or knowing it and for some patterns being able to solve it.  when given such a sigma problem such as n=1 sigma 3 is the end point 7n-1 is the rule, we would use the value of n until the end point 3, but consider 7n-1 equal to 6+13+20 which equals 39 since 7*1-1=6 and 7*2-1=13, 7*3-1=20 and 6+13+20 is 39. remeber it is equal to that since we plug the value of n from the starting point to the end point of any sigma. a1=7*n-1=6,a2=7*2-1=13,  7*3-1=21 is what you should manipulate for another sigma problem that calculates the diffrence of a sequence as well as its total. the one equation that calculates the total of your patterns is:∑_(n=0)^20▒〖7n-0=140〗

the ones i know to find that represent the patterns in terms of what it would be in the nth term is 58ns it represents what the pattern would be in the nth terms but it is not equal to the pattern.

    finding the nth term by looking for an expression to use for the nth term is the same as finding an expression representing the nth term. the nth term is is the numerical difference in the given series with the letter n on the right of that and the number from the beginning of a series in some cases. one more thing for a negative number at the beginning of a pattern you get the missing number i.e the numerical difference on the left and then and the function of the first number. for example:  there is a pattern going from -1 to 19 so the pattern would be -1, 3, 7,11, 15,19. the numerical difference is 4, n is the letter that would come after and -1 , -1 is a function in the area of nth term since the whole expression would be 4n subtracted by 1 and subtraction is a function, a function is a operation in mathes.          

Step-by-step explanation:        

11-5=6

18-11=7

26-35

45-35=10

6+7+35+10=13+45=58 (the differences added up)

5+11+18, 26+35+45​=140