Question

without actually calculating the cubes , find the value of P(2)+P(-2)+P(1)​

Answer 1

Answer:

Identity:1^3+2^3+3^3+4^3+............................n^3={n(n+1)/2}^2

where is no of terms.

here in acc. to ques,

(-1) 3 +(-2) 3 +(-3) 3 + (-4) 3 = -((1) ^3 +(2) ^3 +(3)^ 3 + (4) ^3)

{because -1^3=-1}

= -{4(4+1)/2}^2

= -100

(-1) 3 +(-2) 3 +(-3) 3 + (-4) 3 +2(5) 3 = -100+2*125= -100+250=150