Come si espande # (x-1) ^ 3 #?
Risposta:
#x^3-3x^2+3x-1#
Spiegazione:
#"note that"#
#(x+a)^3=x^3+(a+a+a)x^2+(a.a+a.a+a.a)x+a^3#
#(x-1)^3toa=-1#
#rArr(x-1)^3=x^3+(-1-1-1)x^2+(1+1+1)x+(-1)^3#
#=x^3-3x^2+3x-1#
#x^3-3x^2+3x-1#
#"note that"#
#(x+a)^3=x^3+(a+a+a)x^2+(a.a+a.a+a.a)x+a^3#
#(x-1)^3toa=-1#
#rArr(x-1)^3=x^3+(-1-1-1)x^2+(1+1+1)x+(-1)^3#
#=x^3-3x^2+3x-1#