Mister Exam
Other calculators
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How to use it?
- Equation:
-
Equation cos(x)=2
-
Equation tg(x)=0
- Equation x^2-3x+13=0
- Equation 5^2=5^4
- Express {x} in terms of y where:
- 14*x-16*y=14
- 15*x+15*y=16
- 9*x-8*y=6
- -4*x+18*y=-14
- Derivative of:
- x^2-3x+13
-
Identical expressions
- x^ two -3x+ thirteen = zero
- x squared minus 3x plus 13 equally 0
- x to the power of two minus 3x plus thirteen equally zero
- x2-3x+13=0
- x²-3x+13=0
- x to the power of 2-3x+13=0
- x^2-3x+13=O
-
Similar expressions
- x^2-3x-13=0
- x^2+3x+13=0
x^2-3x+13=0 equation
The teacher will be very surprised to see your correct solution 😉
The solution
Detail solution
This equation is of the form
A quadratic equation can be solved
using the discriminant.
The roots of the quadratic equation:
$$x_{1} = \frac{\sqrt{D} - b}{2 a}$$
$$x_{2} = \frac{- \sqrt{D} - b}{2 a}$$
where D = b^2 - 4*a*c - it is the discriminant.
Because
$$a = 1$$
$$b = -3$$
$$c = 13$$
, then
Because D<0, then the equation
has no real roots,
but complex roots is exists.
or
$$x_{1} = \frac{3}{2} + \frac{\sqrt{43} i}{2}$$
$$x_{2} = \frac{3}{2} - \frac{\sqrt{43} i}{2}$$
a*x^2 + b*x + c = 0
A quadratic equation can be solved
using the discriminant.
The roots of the quadratic equation:
$$x_{1} = \frac{\sqrt{D} - b}{2 a}$$
$$x_{2} = \frac{- \sqrt{D} - b}{2 a}$$
where D = b^2 - 4*a*c - it is the discriminant.
Because
$$a = 1$$
$$b = -3$$
$$c = 13$$
, then
D = b^2 - 4 * a * c =
(-3)^2 - 4 * (1) * (13) = -43
Because D<0, then the equation
has no real roots,
but complex roots is exists.
x1 = (-b + sqrt(D)) / (2*a)
x2 = (-b - sqrt(D)) / (2*a)
or
$$x_{1} = \frac{3}{2} + \frac{\sqrt{43} i}{2}$$
$$x_{2} = \frac{3}{2} - \frac{\sqrt{43} i}{2}$$
Vieta's Theorem
it is reduced quadratic equation
$$p x + q + x^{2} = 0$$
where
$$p = \frac{b}{a}$$
$$p = -3$$
$$q = \frac{c}{a}$$
$$q = 13$$
Vieta Formulas
$$x_{1} + x_{2} = - p$$
$$x_{1} x_{2} = q$$
$$x_{1} + x_{2} = 3$$
$$x_{1} x_{2} = 13$$
$$p x + q + x^{2} = 0$$
where
$$p = \frac{b}{a}$$
$$p = -3$$
$$q = \frac{c}{a}$$
$$q = 13$$
Vieta Formulas
$$x_{1} + x_{2} = - p$$
$$x_{1} x_{2} = q$$
$$x_{1} + x_{2} = 3$$
$$x_{1} x_{2} = 13$$
Rapid solution
[src]
____
3 I*\/ 43
x1 = - - --------
2 2
$$x_{1} = \frac{3}{2} - \frac{\sqrt{43} i}{2}$$
____
3 I*\/ 43
x2 = - + --------
2 2
$$x_{2} = \frac{3}{2} + \frac{\sqrt{43} i}{2}$$
x2 = 3/2 + sqrt(43)*i/2
Sum and product of roots
[src]
sum
____ ____ 3 I*\/ 43 3 I*\/ 43 - - -------- + - + -------- 2 2 2 2
$$\left(\frac{3}{2} - \frac{\sqrt{43} i}{2}\right) + \left(\frac{3}{2} + \frac{\sqrt{43} i}{2}\right)$$
=
3
$$3$$
product
/ ____\ / ____\ |3 I*\/ 43 | |3 I*\/ 43 | |- - --------|*|- + --------| \2 2 / \2 2 /
$$\left(\frac{3}{2} - \frac{\sqrt{43} i}{2}\right) \left(\frac{3}{2} + \frac{\sqrt{43} i}{2}\right)$$
=
13
$$13$$
13
Numerical answer
[src]
x1 = 1.5 - 3.278719262151*i
x2 = 1.5 + 3.278719262151*i
x2 = 1.5 + 3.278719262151*i