Question

the sum 20 terms of the series 1/1.2+ 1/1.4+1/2.3+1/4.7+1/3.4​

Answer 1

Given:

1/1.2+ 1/1.4+1/2.3+1/4.7+1/3.4​

To find:

The sum of the first 20 terms

Solution:

We have given the sequence as

1/1.2+ 1/1.4+1/2.3+1/4.7+1/3.4​ ------------------------

on considering we get to know that here we have the summation of the two sequences which is  

1/1.2+ 1/2.3 +1/3.4​ ------------------ till 10 terms +1/1.4+1/4.7-------till 10 terms

1/1.2+ 1/2.3 +1/3.4​ ------------------ 1/10.11 +1/1.4+1/4.7-------1/28.31

where the sum of the term of this type of series is given by

1/Difference { 1/First term - 1/Last term}

• 1/1(1 - 1/11) + 1/3(1 - 1/31)
• 1(11-1)/11 + 1/3(31-1)/31
• 10/11 + 10/31
• 420/341

Hence, The sum of the first 20 terms is 420/341

Answer 2

Step-by-step explanation:

Pressure is scalar quantity which is defined as force per unit area where the force acts in a direction perpendicular to the surface.