Question

find the 18th term of the AP root√2 ,
3√2,5√2​

Answer 1

Answer:

39√2

Step-by-step explanation:

a = √2

d = a2- a1

d= 3√2-√2

d=2√2

n= 18

an= a+(n-1) d

an = √2+(18-1)2√2

an= √2+17×2√2

an=√2+38√2

an=39√2

Answer 2

Given: A.P. is √2, 3√2, 5√2, …….

To Find: The 18th term of A.P. is √2, 3√2, 5√2, …….

Solution:

• 1st term(a) = √2

The Common difference between (1st term and 2nd term) and (2nd term and 3rd term) is

⇒ d = 2√2

As we know, nth term in an A. P. = a + (n – 1)d

Then, 18th term of A. P. = √2 + (18 – 1)2√2                 [n=18]

                                         = √2 + 17.2√2

                                         = √2 (1+34)

                                         = 35√2

Hence, the answer is : 18th term of A. P. is 35√2.