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Apr
24
revised Find all possible real solutions.
added 4 characters in body; edited title
Apr
20
comment Prove that: $\vdash \forall x(\forall y\alpha)\to \forall y(\forall x \alpha)$
So the swap is not possible if x and y are free in alpha, right? Coz you have used that x and y are not free in alpha. @MauroALLEGRANZA
Apr
20
comment Prove that: $\vdash \forall x \exists !y(y=x)$
Can you exactly state which axiom you have used where? The first axiom states that $\forall x(x=x)$. How have you used it here?
Apr
20
comment Prove that: $\vdash \forall x \exists !y(y=x)$
That is intuitively obvious but I am not able to prove it formally in first order logic @Farnight.
Apr
20
asked Prove that: $\vdash \forall x \exists !y(y=x)$
Apr
20
comment Prove that: $\vdash \forall x(\forall y\alpha)\to \forall y(\forall x \alpha)$
That is what troubles me. I can say something only if x and y are free in α.
Apr
20
asked Prove that: $\vdash \forall x(\forall y\alpha)\to \forall y(\forall x \alpha)$
Apr
19
reviewed Close $\frac{1+\sqrt[3]{\tan x}}{1-2(\cos^2 x)}$
Apr
19
reviewed Approve $\frac{1+\sqrt[3]{\tan x}}{1-2(\cos^2 x)}$
Apr
19
asked How do I prove that $\vDash \alpha \to \forall x\alpha$, if $x$ is not free in $\alpha$
Apr
19
reviewed No Action Needed covariance of random variables
Apr
19
reviewed Looks OK Continuity of $f(x,y,z)=1/(x+y+z-\sqrt{3})$
Mar
25
reviewed No Action Needed Completing this specific integral
Mar
25
comment Prove $\cos(2\theta) + \cos\left(2 \left(\frac{\pi}{3} + \theta\right)\right) +\cos\left(2 \left(\frac{2\pi}{3} + \theta\right)\right) = 0$
Do you know about complex numbers?
Mar
25
reviewed Approve Prove $\cos(2\theta) + \cos\left(2 \left(\frac{\pi}{3} + \theta\right)\right) +\cos\left(2 \left(\frac{2\pi}{3} + \theta\right)\right) = 0$
Mar
25
reviewed Reviewed Which of the following function(s) has/have removable discontinuity at $x=1?$
Mar
24
reviewed Approve Sum of digits produced by a function show repeating numbers/sequences, why?
Mar
24
revised Finding the Locus of Circumcentre
added 2 characters in body
Mar
22
revised Open cover, finite subcover
added 9 characters in body
Mar
22
revised Help with linear differential equation problem
added 54 characters in body