Given that the quadratic equation is (2m+3)x^2+(4m-2)x-(m+1)=0.Find the value of m,if

•one of the root of the equation is negative

•one of the root of the equation is reciprocal of the other

User Icon for Steve Steve answered
10 years ago

the roots are

x = -[(2m-1)±√(6m^2+m+4)]/(2m+3)

The product of the roots is

-(m+1)/(2m+3)
If that is negative, then
(m+1)>0 and (2m+3)>0, so m > -1
(m+1)<0 and (2m+3)<0, so m < -3/2

If the roots are reciprocals, then
-(m+1) = 2m+3
3m = -4
m = -4/3

User Icon for Explain Bot Explain Bot answered
11 months ago

To find the value of m for the given quadratic equation, we'll use two conditions:

Condition 1: One of the roots of the equation is negative.
Condition 2: One of the roots of the equation is the reciprocal of the other.

Let's solve the equation using these conditions step-by-step:

Step 1: Set up the quadratic equation
The given quadratic equation is: (2m+3)x^2 + (4m-2)x - (m+1) = 0

Step 2: Apply the condition of one root being negative
For a quadratic equation of the form ax^2 + bx + c = 0, if one root is negative, then the product of the roots (r1 * r2) will be positive. In our equation, this means that (r1 * r2) > 0.

Using Vieta's formulas, the product of the roots is given by c / a. Therefore, we have:
(m+1) / (2m+3) > 0

Step 3: Analyze the condition
To satisfy the condition, the product (m+1) / (2m+3) must be greater than 0. This means both the numerator (m+1) and denominator (2m+3) should either be positive or negative.

Case 1: Numerator and denominator are both positive
If (m+1) > 0 and (2m+3) > 0, we have two possible inequalities:
m > -1 and m > -3/2

Taking the intersection of these two inequalities, we get m > -1.

Case 2: Numerator and denominator are both negative
If (m+1) < 0 and (2m+3) < 0, we have two possible inequalities:
m < -1 and m < -3/2

Taking the intersection of these two inequalities, we get m < -3/2. However, since we're looking for the value of m where one root is negative, this case is not valid.

Step 4: Apply the condition of one root being the reciprocal of the other
For a quadratic equation of the form ax^2 + bx + c = 0, if one root is the reciprocal of the other, then the sum of the roots (r1 + r2) will be zero. In our equation, this means that (r1 + r2) = 0.

Using Vieta's formulas, the sum of the roots is given by -b / a. Therefore, we have:
-(4m-2) / (2m+3) = 0

Step 5: Analyze the condition
To satisfy the condition, the sum (-(4m-2) / (2m+3)) must be equal to zero. This means the numerator -(4m-2) must be zero.

Solving -(4m-2) = 0, we get 4m-2 = 0, then 4m = 2, and finally, m = 1/2.

Step 6: Combine the conditions
To find the valid value of m that satisfies both conditions, we need to find the intersection of m > -1 from the first condition and m = 1/2 from the second condition.

Since m = 1/2 is the solution that satisfies both conditions, the value of m is 1/2.

Therefore, when m = 1/2, the given quadratic equation satisfies the conditions: one root is negative, and one root is the reciprocal of the other.