plz prove this . it's urgent
Answers
Answer:
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Question:-
If α and β are the roots of the equation x² + px + q = 0 and α = β² , then prove that p³ + q² + q = 3pq
Answer:-
Given quadratic equation is x² + px + q = 0.
On comparing with standard form of a Quadratic equation , i.e., ax² + bx + c = 0,
Let ,
- a = 1
- b = p
- c = q
We know that,
Sum of the zeroes = - b/a
⟶ α + β = - p/1
⟶ α + β = - p
⟶ - α - β = p
Substitute the value of α from equation (1).
⟶ - α - β = p -- equation (1)
Product of the zeroes = c/a
⟶ αβ = q -- equation (2)
Also given that,
α = β² -- equation (3)
We have to prove :
p³ + q² + q = 3pq
Substitute the values of p and q from equations (1) & (2).
⟶ (- α - β)³ + (αβ)² + αβ = 3(- α - β)(αβ)
- (a - b)³ = a³ - b³ - 3ab(a - b)
⟶ (- α)³ - (β)³ - 3( - α)(β) (- α - β) + (αβ)² + αβ = 3 [ αβ ( - α) + αβ ( - β) ]
⟶ - α³ - β³ + 3αβ( - α - β) + (αβ)² + αβ = 3 [ - α²β - αβ² ]
⟶ - α³ - β³ - 3α²β - 3αβ² + (αβ)² + αβ = 3 ( - α²β - αβ² )
⟶ - (β²)³ - β³ - 3(β²)²(β) - 3(β²)(β²) + (β²)²(β)² + (β²)(β) = 3 [ - (β²)²(β) - (β²)(β²) ]
[ From equation (1) ]
⟶ - β⁶ - β³ - 3β⁵ - 3β⁴ + β⁶ + β³ = 3 ( - β⁵ - β⁴ )
⟶ - 3β⁵ - 3β⁴ = - 3β⁵ - 3β⁴
Hence Proved.