Let take the number be 600851475143, so to find the largest prime factor run the following code
Result : 6857
<?php
$max = 600851475143;
$l_num = 0;
for ($j = floor(sqrt($max)) / 2; $j >= 2;...
Sum of first n terms of A.P will be n2
Explanation :
n1=7
Sn=49
we know that Sn = n/2{2a+(n-1)d}
thus,
Sn1=7/2(2a+6d)=49
=14a+42d=98 ... (1) x17
n2=17
Sn2=289
Sn2=17/2(2a+16d)=289
=34a+272d=578 ....(2) x7
from eq 1 & 2
238a +714d =1666 ...
The multiples of 8 are
8, 16, 24, 32…
These are in an A.P., having first term as 8 and common difference as 8.
Therefore, a = 8
d = 8
S15 = ?
Sn = n/2 [2a + (n - 1)d]
S15 = 15/2 [2(8) + (15 -...
Let the three consecutive multiples of 8 be x, x+8 and x+16.
According to question,
x+x+8+x+16=888 [Subtracting 24 from both sides]
=> 3x=864
=> 3x/3=864/3 [Dividing both sides by3]
=> x = 288
Hence, first multiple of...
Solution: Smallest number divisible by 4 after 10 is 12, The greatest number below 250 which is divisible by 4 is 248
Number of terms: {(248-12)/4}+1
{236/4}+1 = 59+1 = 60
