promath In this post, we will prove tanx + tany + tanz = tanx tany tanz when x+y+z is equal to π. Here we will use the following formula: tan(x+y) = $\dfrac{\tan x+\tan y}{1-\tan x \tan y}$. Question: If x+y+z=π, then prove that tanx + tany + tanz = tanx tany tanz. Solution: Given that x+y+z=π. … Read more
The formula of tan(x+y+z) is given as follows: tan(x+y+z) = $\dfrac{\tan x +\tan y+\tan z – \tan x \tan y \tan z}{1-\tan x \tan y-\tan y \tan z-\tan z \tan x}$. In this post, let us learn how to prove the formula of tan(x+y+z). Proof of tan(x+y+z) Formula We will use the formula tan(a+b) = … Read more
The cos(x+y+z) formula is given by cos(x+y+z) = cosx cosy cosz – sinx siny cosz – sinx cosy sinz – cosx siny sinz. Here we establish the identity of cos(x+y+z). Formula of cos(x+y+z) The formula of cos(x+y+z) is given below: $\cos(x+y+z) = \cos x \cos y \cos z – \sin x \sin y \cos z … Read more
The sin(x+y+z) identity is given by sin(x+y+z) = sinx cosy cosz + cosx siny cosz + cosx cosy sinz – sinx siny sinz. In this post, we will establish the formula of sin(x+y+z). Formula of sin(x+y+z) The formula of sin(x+y+z) is given as follows: $\sin(x+y+z) = \sin x \cos y \cos z + \cos x … Read more
The solution of the differential equation dy/dx=1+x+y+xy is equal to y= 1 – $C e^{x +\frac{x^2}{2}}$ where C is an arbitrary constant. In this post, we will learn how to solve dy/dx=1+x+y+xy. Solution of dy/dx=1+x+y+xy Question: Solve the differential equation $\dfrac{dy}{dx}$ = 1+x+y+xy. Solution: We will solve solve $\dfrac{dy}{dx}$ =1+x+y+xy by variable separable method. The … Read more
The exact solution of dy/dx=x+y is equal to |x+y+1| = Cex where C is a constant. In this post, we will learn how to solve the differential equation dy/dx =x+y. Solve dy/dx=x+y Question: Find the general solution of $\dfrac{dy}{dx}=x+y$. Solution: To solve the given differential equation, we will use the substitute method. Let us put … Read more
The simplification of cos3x -sin3x is equal to cos3x -sin3x = (cosx -sinx)(2+sin2x)/2. The formula of cos^3x +sin^3x is given as follows: cos3x +sin3x = $\dfrac{(\cos x +\sin x)(2-\sin 2x)}{2}$. Formula of cos3x -sin3x Prove that cos3x -sin3x = (cosx -sinx)(2+sin2x)/2. Solution: Applying the formula a3 -b3 = (a -b)(a2+ab+b2), we get that cos3x -sin3x … Read more
The partial derivative of xy with respect to x is equal to y and the partial derivative of xy with respect to y is equal to x. Their formula is given below: Partial Derivative of xy with respect to x Let us will find the partial derivative of xy using the definition. Let f(x, y) … Read more
The derivative of x/y with respect to x is equal to (-x dy/dx + y)/y2. Here, we will learn how to differentiate x/y with respect to x. Derivative of x/y with respect to x Question: Differentiate x/y with respect to x. Solution: Note that $\dfrac{x}{y}$ is a product of two functions $x$ and $\dfrac{1}{y}$. So … Read more
The derivative of the mod cosx is equal to (- sinx cosx)/|cosx|. Here let us learn how to differentiate mod cosx, that is, how to find d/dx(|cosx|). The derivative formula of mod cosx is given as follows. $\boxed{\dfrac{d}{dx}(|\cos x|)=\dfrac{-\sin x \cos x}{|\cos x|}}$, provided that cosx is non-zero. The following formula is very useful to … Read more