Question

solve plz plz plz plz ​

Answer 1

hlww....

since,

${1}^{3} + {2}^{3} + {3}^{3}.... + {20}^{3} \\ = (\frac{20 \times 21}{2} )sq \\ = {210}^{2} \\ = 44100$

Answer 2

Question

1+2+3+4+5.......+20= 210

$1^3 + 2^3 + 3^3.......+ 20^3$ = ?

ANSWER

Here the following sequence can be solved by a very special formula which is=>

$1^3 + 2^3 + n^3$= $\dfrac{n(n+1)(n+1)}{2}$

By using this formula we can find the value of this expression.

So, we get =>

$1^3+2^3...............+20^3$

=>$20\times\dfrac{20+1}{2}}^2$

=> $\dfrac{(20)(21)}{2}}^2$

=> ${10\times21}^2$

=> ${210}^2$

=>44100.

Hence the value of given expression is 44100.

Remember

$1^3 + 2^3 + n^3$= $n\times\dfrac{(n+1)(n+1)}{2}$