Advertisements
Advertisements
प्रश्न
The sum of first n natural numbers is given by `1/2n^2 + 1/2n`. Find the sum of first 5 natural numbers.
उत्तर
Given, sum of first n natural numbers = `1/2n^2 + 1/2n`
Sum of first 5 natural numbers = `1/2(5)^2 + 1/2(5)` ......[Put n = 5]
= `25/2 + 5/2`
= `30/2`
= 15
APPEARS IN
संबंधित प्रश्न
Observe the patterns of digits made from line segments of equal length. You will find such segmented digits on the display of electronic watches or calculators.
If the number of digits formed is taken to be n, the number of segments required to form n digits is given by the algebraic expression appearing on the right of each pattern.
How many segments are required to form 5, 10, 100 digits of the kind −
Write down the following in the product form: 9xy2z
If 9 is added to a certain number, the result is 36. Find the number.
Find a number which when multiplied by 5 is increased by 80.
When Raju multiplies a certain number by 17 and adds 4 to the product, he gets 225. Find that number.
If a number is tripled and the result is increased by 5, we get 50. Find the number.
A man is 4 times as old as his son. After 16 years he will be only twice as old as his son. Find their present ages.
If I spend f rupees from 100 rupees, the money left with me is ______ rupees.
If m is a whole number, then 2 m denotes a multiple of 2.
The side of an equilateral triangle is shown by l. Express the perimeter of the equilateral triangle using l.
The side of a regular hexagon is denoted by l. Express the perimeter of the hexagon using l.
(Hint: A regular hexagon has all its six sides equal in length.)
A cube is a three-dimensional figure as shown in the given figure. It has six faces and all of them are identical squares. The length of an edge of the cube is given by l. Find the formula for the total length of the edges of a cube.
The side length of the top of square table is x. The expression for perimeter is ______.
The speed of car is 55 km/hrs. The distance covered in y hours is ______.
The sum of squares of first n natural numbers is given by `1/6n(n + 1)(2n + 1)` or `1/6(2n^3 + 3n^2 + n)`. Find the sum of squares of the first 10 natural numbers.
The sum of the multiplication table of natural number ‘n’ is given by 55 × n. Find the sum of table of 7.
The sum of the multiplication table of natural number ‘n’ is given by 55 × n. Find the sum of table of 19.
If 
= 2x + 3, 
= `3/2x + 7` and 
= x – 3 then find the value of:
`1/2`
+ 
– 3
