P(x) =5x^5+ 3x - 4x^4- 2 x^3 +6 + 4x^2 Q(X) = 2x^4 - x +3x^2 - 2x^3+ 1/4 - x^5 a/ Sắp xếp mỗi hạng tử của đa thức theo luỹ thừa giảm cuả biến. b/ Tính: P(x) +Q(x); P(x) -Q(x)
1 câu trả lời
a, P(x) = 5$x^5$ + 3x - 4$x^4$ - 2$x^3$ + 6 + 4$x^2$
P(x) = 5$x^5$ - 4$x^4$ - 2$x^3$ + 4$x^2$ + 3x + 6
Q(x) = 2$x^4$ - x + 3$x^2$ - 2$x^3$ + $\dfrac{1}{4}$ - $x^5$
Q(x) = - $x^5$ + 2$x^4$ - 2$x^3$ + 3$x^2$ - x + $\dfrac{1}{4}$
b,
P(x) + Q(x) = (5$x^5$ - 4$x^4$ - 2$x^3$ + 4$x^2$ + 3x + 6) + (- $x^5$ + 2$x^4$ - 2$x^3$ + 3$x^2$ - x + $\dfrac{1}{4}$)
P(x) + Q(x) = 5$x^5$ - 4$x^4$ - 2$x^3$ + 4$x^2$ + 3x + 6 + - $x^5$ + 2$x^4$ - 2$x^3$ + 3$x^2$ + $\dfrac{1}{4}$
P(x) + Q(x) = (5$x^5$ - $x^5$) + (- 4$x^4$ + 2$x^4$) - (2$x^3$ + 2$x^3$) + ( 4$x^2$ + 3$x^2$) + (3x - x) + ( 6 + $\dfrac{1}{4}$ )
P(x) + Q(x) = 4$x^5$ - 2$x^4$ - 4$x^3$ + 7$x^2$ + 2x + $\dfrac{25}{4}$
P(x) - Q(x) = (5$x^5$ - 4$x^4$ - 2$x^3$ + 4$x^2$ + 3x + 6) - (- $x^5$ + 2$x^4$ - 2$x^3$ + 3$x^2$ - x + $\dfrac{1}{4}$)
P(x) - Q(x) = 5$x^5$ - 4$x^4$ - 2$x^3$ + 4$x^2$ + 3x + 6 + $x^5$ - 2$x^4$ + 2$x^3$ - 3$x^2$ + x - $\dfrac{1}{4}$
P(x) - Q(x) = ( 5$x^5$ + $x^5$) - ( 4$x^4$ + 2$x^4$ ) + (2$x^3$ - 2$x^3$) + (4$x^2$ - 3$x^2$ ) + (3x +x) + (6 - $\dfrac{1}{4}$ )
p(x) - Q(x) = 6$x^5$ - 6$x^4$ + $x^2$ + 4x + $\dfrac{23}{4}$