promath The tan(π-x) formula is given by tan(π-x)= -tanx. The formula of tan(pi-θ) is equal to tan(π-θ)= -tanθ. In this post, we will learn how to compute tan(pi-x) and tan(θ-pi). Note that Proof of tan(pi-x) Formula Let us use the formula: tan(a-b) = $\dfrac{\tan a -\tan b}{1+\tan a \tan b}$ …(∗) Put a=π, b=x. Thus, we … Read more
In this post, we will prove (1+tanx)(1+tany)=2 when x+y is equal to π/4 =45°. To prove this, we will use the following formula: tan(x+y) = $\dfrac{\tan x+\tan y}{1-\tan x \tan y}$. Question: If x+y=π/4, then prove that (1+tanx)(1+tany)=2. Solution: Step 1: Given that x+y=π/4. Therefore, tan(x+y) = tan(π/4) ⇒ $\dfrac{\tan x+\tan y}{1-\tan x \tan y}$ … Read more
The derivative of e^cosx (e to the power cosx) is equal to -sinx ecosx. In this post, we will find the derivative of ecosx by first principle. The derivative formula of ecosx is given below: $\dfrac{d}{dx}$(ecosx) = -sinx ecosx. Derivative of e^cosx Using First Principle By first principle, the derivative of a function f(x) using … Read more
The derivative of e^sinx is equal to cosx esinx. In this post, we will find the derivative of esinx by first principle. The esinx derivative formula is given as follows: $\dfrac{d}{dx}$(esinx) = cosx esinx. Derivative of e^sinx Using First Principle The derivative of f(x) using the first principle is given by the following limit formula: … Read more
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