Mathematics
Find p(0), p(1) and p(2) for each of the following polynomials:
(i) p(y) = y2 - y + 1
(ii) p(t) = 2 + t + 2t2 - t3
(iii) p(x) = x3
(iv) p(x) = (x - 1) (x + 1)
Answer
(i) p(y) = y2 - y + 1
Putting y = 0 we get,
p(0) = (0)2 - 0 + 1
= 0 - 0 + 1
= 1
∴ p(0) = 1
Putting y = 1 we get,
p(1) = (1)2 - 1 + 1
= 1 - 1 + 1
= 2 - 1
= 1
∴ p(1) = 1
Putting y = 2 we get,
p(2) = (2)2 - 2 + 1
= 4 - 2 + 1
= 5 - 2
= 3
∴ p(2) = 1
Hence, for p(y) = y2 - y + 1, p(0) = 1, p(1) = 1 and p(2) = 1
(ii) p(t) = 2 + t + 2t2 - t3
Putting t = 0 we get,
p(0) = 2 + 0 + 2(02) - 03
= 2 + 0 + 0 - 0
= 2
∴ p(0) = 2
Putting t = 1 we get,
p(1) = 2 + 1 + 2(12) - 13
= 2 + 1 + 2 - 1
= 4
∴ p(1) = 4
Putting t = 2 we get,
p(2) = 2 + 2 + 2(22) - 23
= 4 + 2(4) - 8
= 4 + 8 - 8
= 4
∴ p(2) = 4
Hence, for p(t) = 2 + t + 2t2 - t3, p(0) = 2, p(1) = 4 and p(2) = 4
(iii) p(x) = x3
Putting x = 0 we get,
p(0) = (0)3
= 0
∴ p(0) = 0
Putting x = 1 we get,
p(1) = (1)3
= 1
∴ p(1) = 1
Putting x = 2 we get,
p(2) = (2)3
= 8
∴ p(2) = 8
Hence, for p(x) = x3, p(0) = 0, p(1) = 1 and p(2) = 8
(iv) p(x) = (x - 1)(x + 1)
Putting x = 0 we get,
p(0) = (0 - 1)(0 + 1)
= (-1) x 1
= (-1)
∴ p(0) = -1
Putting x = 1 we get,
p(1) = (1 - 1)(1 + 1)
= 0 x 2
= 0
∴ p(1) = 0
Putting x = 2 we get
p(2) = (2 - 1) (2 + 1)
= 1 x 3
= 3
∴ p(2) = 3
Hence, for p(x) = (x - 1) (x + 1), p(0) = -1, p(1) = 0 and p(2) = 3
Related Questions
Classify the following as linear, quadratic and cubic polynomials:
(i) x2 + x
(ii) x - x3
(iii) y + y2 + 4
(iv) 1 + x
(v) 3t
(vi) r2
(vii) 7x3
Find the value of the polynomial 5x - 4x2 + 3 at
(i) x = 0
(ii) x = -1
(iii) x = 2
Find the zero of the polynomial in each of the following cases:
(i) p(x) = x + 5
(ii) p(x) = x - 5
(iii) p(x) = 2x + 5
(iv) p(x) = 3x - 2
(v) p(x) = 3x
(vi) p(x) = ax, a ≠ 0
(vii) p(x) = cx + d, c ≠ 0, c, d are real numbers.