Find the minimum value of the curve 12x2 + 24x + 13. 11. If the roots of ax2 + bx + c = 0 are alpha and beta, show that alpha + beta = -(b)/(a) and alphabeta = (c)/(a).
|Mathematics
Find the minimum value of the curve 12x2 + 24x + 13. 11. If the roots of ax2 + bx + c = 0 are alpha and beta, show that alpha + beta = -(b)/(a) and alphabeta = (c)/(a).
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Answer
1
Here are the solutions to problems 10, 11, and 12.
10. Find the minimum value of the curve 12x2+24x+13.
The given curve is a quadratic function y=12x2+24x+13.
This is in the form y=ax2+bx+c, where a=12, b=24, and c=13.
Since a=12>0, the parabola opens upwards, meaning it has a minimum value.
The minimum value occurs at the vertex of the parabola, where the x-coordinate is given by x=−2ab.
Step 1: Find the x-coordinate of the vertex.
x=−2(12)24x=−2424x=−1
Step 2: Substitute this x-value back into the equation to find the minimum y-value.
y=12(−1)2+24(−1)+13y=12(1)−24+13y=12−24+13y=−12+13y=1
The minimum value of the curve is 1.
11. If the roots of ax2+bx+c=0 are α and β, show that α+β=−ab and αβ=ac.
Step 1: Use the quadratic formula to express the roots α and β.
The roots of the quadratic equation ax2+bx+c=0 are given by:
α=2a−b+b2−4acβ=2a−b−b2−4ac
Step 2: Find the sum of the roots, α+β.
α+β=2a−b+b2−4ac+2a−b−b2−4acα+β=2a(−b+b2−4ac)+(−b−b2−4ac)α+β=2a−b−b+b2−4ac−b2−4acα+β=2a−2bα+β=−ab
Step 3: Find the product of the roots, αβ.
αβ=(2a−b+b2−4ac)(2a−b−b2−4ac)
This is in the form (X+Y)(X−Y)=X2−Y2, where X=−b and Y=b2−4ac.
αβ=(2a)2(−b)2−(b2−4ac)2αβ=4a2b2−(b2−4ac)αβ=4a2b2−b2+4acαβ=4a24acαβ=ac
Thus, we have shown that α+β=−ab and αβ=ac.
12. Find b if h(x)=2x−1 is a factor of f(x)=6x2+bx+2.
Step 1: Use the Factor Theorem. If h(x) is a factor of f(x), then f(k)=0 for the root k of h(x)=0.
First, find the root of h(x)=2x−1:
2x−1=02x=1x=21
Step 2: Substitute this root into f(x) and set f(x)=0.
f(21)=6(21)2+b(21)+2=0
Step 3: Solve the equation for b.
6(41)+2b+2=046+2b+2=023+2b+2=0
To eliminate fractions, multiply the entire equation by 2:
2(23)+2(2b)+2(2)=2(0)3+b+4=0b+7=0b=−7
The value of b is −7.
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Find the x-coordinate of the vertex. x = -(24)/(2(12)) x = -(24)/(24) x = -1 Step 2: Substitute this x-value back into the equation to find the minimum y-value.
Find the minimum value of the curve 12x2 + 24x + 13. 11. If the roots of ax2 + bx + c = 0 are alpha and beta, show that alpha + beta = -(b)/(a) and alphabeta = (c)/(a).
This mathematics problem involves applying core mathematical principles and formulas. Below you will find a complete step-by-step solution with detailed explanations for each step, helping you understand not just the answer but the method behind it.
ScanSolve AI Answer
Here are the solutions to problems 10, 11, and 12. 10. Find the minimum value of the curve 12x^2 + 24x + 13. The given curve is a quadratic function y = 12x^2 + 24x + 13. This is in the form y = ax^2 + bx + c, where a=12, b=24, and c=13. Since a=12 > 0, the parabola opens upwards, meaning it has a minimum value. The minimum value occurs at the vertex of the parabola, where the x-coordinate is given by x = -(b)/(2a). Step 1: Find the x-coordinate of the vertex. x = -(24)/(2(12)) x = -(24)/(24) x = -1 Step 2: Substitute this x-value back into the equation to find the minimum y-value. y = 12(-1)^2 + 24(-1) + 13 y = 12(1) - 24 + 13 y = 12 - 24 + 13 y = -12 + 13 y = 1 The minimum value of the curve is 1. 11. If the roots of ax^2 + bx + c = 0 are and , show that + = -(b)/(a) and = (c)/(a). Step 1: Use the quadratic formula to express the roots and . The roots of the quadratic equation ax^2 + bx + c = 0 are given by: = -b + sqrt(b^2 - 4ac)2a = -b - sqrt(b^2 - 4ac)2a Step 2: Find the sum of the roots, + . + = -b + sqrt(b^2 - 4ac)2a + -b - sqrt(b^2 - 4ac)2a + = (-b + sqrt(b^2 - 4ac)) + (-b - sqrt(b^2 - 4ac))2a + = -b - b + sqrt(b^2 - 4ac) - sqrt(b^2 - 4ac)2a + = (-2b)/(2a) + = -(b)/(a) Step 3: Find the product of the roots, . = (-b + sqrt(b^2 - 4ac)2a) (-b - sqrt(b^2 - 4ac)2a) This is in the form (X+Y)(X-Y) = X^2 - Y^2, where X = -b and Y = sqrt(b^2 - 4ac). = (-b)^2 - (sqrt(b^2 - 4ac))^2(2a)^2 = (b^2 - (b^2 - 4ac))/(4a^2) = (b^2 - b^2 + 4ac)/(4a^2) = (4ac)/(4a^2) = (c)/(a) Thus, we have shown that + = -(b)/(a) and = (c)/(a). 12. Find b if h(x) = 2x-1 is a factor of f(x) = 6x^2 + bx + 2. Step 1: Use the Factor Theorem. If h(x) is a factor of f(x), then f(k)=0 for the root k of h(x)=0. First, find the root of h(x) = 2x-1: 2x - 1 = 0 2x = 1 x = (1)/(2) Step 2: Substitute this root into f(x) and set f(x)=0. f((1)/(2)) = 6((1)/(2))^2 + b((1)/(2)) + 2 = 0 Step 3: Solve the equation for b. 6((1)/(4)) + (b)/(2) + 2 = 0 (6)/(4) + (b)/(2) + 2 = 0 (3)/(2) + (b)/(2) + 2 = 0 To eliminate fractions, multiply the entire equation by 2: 2((3)/(2)) + 2((b)/(2)) + 2(2) = 2(0) 3 + b + 4 = 0 b + 7 = 0 b = -7 The value of b is -7.