Mister Exam
Other calculators
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How to use it?
- Equation:
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Equation 2x=18-x
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Equation 9*x^2=54*x
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Equation cos(x)=-2
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Equation 2*x^2+6*x+9=
- Express {x} in terms of y where:
- 14*x+16*y=-3
- -10*x-18*y=15
- 20*x+5*y=-3
- 4*x+18*y=-14
- Derivative of:
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cos(x)
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-2
- Graphing y =:
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cos(x)
- Integral of d{x}:
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cos(x)
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-2
- Sum of series:
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-2
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Identical expressions
- cos(x)=- two
- co sinus of e of (x) equally minus 2
- co sinus of e of (x) equally minus two
- cosx=-2
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Similar expressions
- 2cosx+1=0
- 2*cos(x/2)^2+sqrt(3)*cos(x/2)=0
- (cos(2*x)*cos(8*x)-cos(10*x))/cos(x+1)=0
- cos(x)=+2
- cosx=-2
cos(x)=-2 equation
The teacher will be very surprised to see your correct solution 😉
The solution
Detail solution
Given the equation
$$\cos{\left(x \right)} = -2$$
- this is the simplest trigonometric equation
As right part of the equation
modulo =
but cos
can no be more than 1 or less than -1
so the solution of the equation d'not exist.
$$\cos{\left(x \right)} = -2$$
- this is the simplest trigonometric equation
As right part of the equation
modulo =
True
but cos
can no be more than 1 or less than -1
so the solution of the equation d'not exist.
Rapid solution
[src]
x1 = -re(acos(-2)) + 2*pi - I*im(acos(-2))
$$x_{1} = - \operatorname{re}{\left(\operatorname{acos}{\left(-2 \right)}\right)} + 2 \pi - i \operatorname{im}{\left(\operatorname{acos}{\left(-2 \right)}\right)}$$
x2 = I*im(acos(-2)) + re(acos(-2))
$$x_{2} = \operatorname{re}{\left(\operatorname{acos}{\left(-2 \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(-2 \right)}\right)}$$
Sum and product of roots
[src]
sum
0 + -re(acos(-2)) + 2*pi - I*im(acos(-2)) + I*im(acos(-2)) + re(acos(-2))
$$\left(\operatorname{re}{\left(\operatorname{acos}{\left(-2 \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(-2 \right)}\right)}\right) - \left(- 2 \pi + \operatorname{re}{\left(\operatorname{acos}{\left(-2 \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(-2 \right)}\right)}\right)$$
=
2*pi
$$2 \pi$$
product
1*(-re(acos(-2)) + 2*pi - I*im(acos(-2)))*(I*im(acos(-2)) + re(acos(-2)))
$$\left(\operatorname{re}{\left(\operatorname{acos}{\left(-2 \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(-2 \right)}\right)}\right) 1 \left(- \operatorname{re}{\left(\operatorname{acos}{\left(-2 \right)}\right)} + 2 \pi - i \operatorname{im}{\left(\operatorname{acos}{\left(-2 \right)}\right)}\right)$$
=
-(I*im(acos(-2)) + re(acos(-2)))*(-2*pi + I*im(acos(-2)) + re(acos(-2)))
$$- \left(\operatorname{re}{\left(\operatorname{acos}{\left(-2 \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(-2 \right)}\right)}\right) \left(- 2 \pi + \operatorname{re}{\left(\operatorname{acos}{\left(-2 \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(-2 \right)}\right)}\right)$$
-(i*im(acos(-2)) + re(acos(-2)))*(-2*pi + i*im(acos(-2)) + re(acos(-2)))
Numerical answer
[src]
x1 = 3.14159265358979 + 1.31695789692482*i
x2 = 3.14159265358979 - 1.31695789692482*i
x2 = 3.14159265358979 - 1.31695789692482*i
The graph