Derivative of Hyperbolic Functions
Before getting into the details of the derivative of hyperbolic functions, let us recall the concept of the hyperbolic functions. Hyperbolic functions are functions in calculus that are expressed as combinations of the exponential functions ex and e-x. We have six main hyperbolic functions given by, sinhx, coshx, tanhx, sechx, cothx, and cschx. The derivative of hyperbolic functions is calculated using the derivatives of exponential functions formula and other hyperbolic functions formulas and identities.
In this article, we will evaluate the derivatives of hyperbolic functions using different hyperbolic trig identities and derive their formulas. We will also explore the graphs of the derivative of hyperbolic functions and solve examples and find derivatives of functions using these derivatives for a better understanding of the concept.
What is Derivative of Hyperbolic Functions?
The derivative of hyperbolic functions gives the rate of change in the hyperbolic functions as differentiation of a function determines the rate of change in function with respect to the variable. We can evaluate these derivatives using the derivative of exponential functions ex and e-x along with other hyperbolic functions formulas and identities. We have six main hyperbolic functions namely,
- Sinhx
- Coshx
- Tanhx
- Cothx
- Sechx
- Cschx
The derivative of hyperbolic functions is used in describing the shape of electrical wires hanging freely between two poles. They are also used to describe any freely hanging cable between two ends. Among other applications, the derivative of hyperbolic functions is used to describe the formation of satellite rings and planets. In the next section, we will explore the formulas of the derivatives of hyperbolic functions.
Derivative of Hyperbolic Functions Formula
Now, we will go through the formulas of the derivatives of hyperbolic functions. The hyperbolic functions are combinations of exponential functions ex and e-x. Given below are the formulas for the derivative of hyperbolic functions:
- Derivative of Hyperbolic Sine Function: d(sinhx)/dx = coshx
- Derivative of Hyperbolic Cosine Function: d(coshx)/dx = sinhx
- Derivative of Hyperbolic Tangent Function: d(tanhx)/dx = sech2x
- Derivative of Hyperbolic Cotangent Function: d(cothx)/dx = -csch2x (x ≠ 0)
- Derivative of Hyperbolic Secant Function: d(sechx)/dx = -sechx tanhx
- Derivative of Hyperbolic Cosecant Function: d(cschx)/dx = -cschx cothx (x ≠ 0)
Let us now prove these derivatives using different mathematical formulas and identities.
Derivatives of Hyperbolic Functions Proof
Now that we know the formulas for the derivatives of hyperbolic functions, let us now prove them using various formulas and identities of hyperbolic functions. We will use the following formulas to prove the derivative of hyperbolic functions:
- Derivative of e to the power x: d(ex)/dx = ex
- Derivative of e to the power negative x: d(e-x)/dx = -e-x
Derivative of Sinhx
We know that the formula for sinhx is given by, sinhx = (ex - e-x)/2. To find the derivative of hyperbolic function sinhx, we will write as a combination of exponential function and differentiate it using the quotient rule of differentiation. Also, we know that we can write the hyperbolic function cosh x as cosh x = (ex + e-x)/2. So, using these formulas, we have
d(sinhx)/dx = d[(ex - e-x)/2] / dx
= [ (ex - e-x)' 2 - (ex - e-x) (2)' ] / 22
= [ex - (-e-x)] 2 / 22 --- [Using d(ex)/dx = ex and d(e-x)/dx = -e-x]
= (ex + e-x)/2
= cosh x
Therefore, the derivative of sinh x is equal to cosh x.
Derivative of Coshx
To prove the derivative of coshx, we will use the following formulas:
- sinhx = (ex - e-x)/2
- cosh x = (ex + e-x)/2
- d(ex)/dx = ex
- d(e-x)/dx = -e-x
Using the above formulas, we have
d(coshx)/dx = d[(ex + e-x)/2] / dx
= d(ex/2) / dx + d(e-x/2) / dx
= ex/2 - e-x/2
= (ex - e-x)/2
= sinhx
Hence, we have proved that the derivative of coshx is equal to sinhx.
Derivative of Tanhx
Using hyperbolic functions formulas, we know that tanhx can be written as the ratio of sinhx and coshx. So, we will use the quotient rule and the following formulas to find the derivative of tanhx:
- tanhx = sinhx / coshx
- d(sinhx)/dx = coshx
- d(coshx)/dx = sinhx
- cosh2x - sinh2x = 1
- 1/coshx = sechx
Using the above formulas, we have
d(tanhx)/dx = d(sinhx / coshx)/dx
= [(sinhx)2 coshx - (coshx)' sinhx] / cosh2x --- [Using quotient rule of derivatives]
= (cosh2x - sinh2x) / cosh2x
= 1 / cosh2x
= sech2x
Hence, the derivative of hyperbolic function tanhx is equal to sech2x.
Derivative of Cothx
Just like we derived the derivative of tanhx, we will evaluate the derivative of hyperbolic function cothx using the quotient rule. Also, we can express cothx as the ratio of coshx and sinhx. We will use the following formulas to calculate the derivative of tanhx:
- cothx = coshx/sinhx
- d(sinhx)/dx = coshx
- d(coshx)/dx = sinhx
- cosh2x - sinh2x = 1
- 1/sinhx = cschx
So, we have
d(cothx)/dx = d(coshx/sinhx)/dx
= [(coshx)' sinhx - (sinhx)' coshx] / sinh2x
= (sinh2x - cosh2x) / sinh2x
= -(cosh2x - sinh2x) / sinh2x
= -1 / sinh2x
= - csch2x
Therefore, the derivative of cothx is equal to - csch2x.
Derivative of Sechx
In this section, we will derive the formula for the derivative of sechx using the quotient rule. We will use the formula for the derivative of coshx along with other formulas given by,
- d(coshx)/dx = sinhx
- sechx = 1/coshx
- tanhx = sinhx/coshx
Using the above formulas, we have
d(sechx)/dx = d(1/coshx)/dx
= [(1)' coshx - (coshx)' (1)] / cosh2x
= (0 × coshx - sinhx) / cosh2x
= -sinhx / cosh2x
= - (sinhx / coshx) × (1/coshx)
= - tanhx sechx
Hence, the derivative of hyperbolic function sechx is equal to - tanhx sechx.
Derivative of Cschx
To find the derivative of cschx, we will use a similar method as we used to find the derivative of sechx. We will use the following formulas to find the derivative of cschx:
- d(sinhx)/dx = coshx
- 1/sinhx = cschx
- cothx = coshx/sinhx
So, we have
d(cschx)/dx = d(1/sinhx)/dx
= [(1)' sinhx - (sinhx)' (1)] / sinh2x
= (0 × sinhx - coshx) / sinh2x
= -coshx / sinh2x
= - (coshx / sinhx) × (1/sinhx)
= - cothx cschx (x ≠ 0)
Hence, we have proved that the derivative of cschx is equal to - cothx cschx.
Derivative of Inverse Hyperbolic Functions
Now that we have derived the derivative of hyperbolic functions, we will derive the formulas of the derivatives of inverse hyperbolic functions. We can find the derivatives of inverse hyperbolic functions using the implicit differentiation method. We have six main inverse hyperbolic functions, given by arcsinhx, arccoshx, arctanhx, arccothx, arcsechx, and arccschx. Their derivatives are given by:
- Derivative of arcsinhx: d(arcsinhx)/dx = 1/√(x2 + 1), -∞ < x < ∞
- Derivative of arccoshx: d(arccoshx)/dx = 1/√(x2 - 1), x > 1
- Derivative of arctanhx: d(arctanhx)/dx = 1/(1 - x2), |x| < 1
- Derivative of arccothx: d(arccothx)/dx = 1/(1 - x2), |x| > 1
- Derivative of arcsechx: d(arcsechx)/dx = -1/x√(1 - x2), 0 < x < 1
- Derivative of arccschx: d(arccschx)/dx = -1/|x|√(1 + x2), x ≠ 0
Now, let use derive the above formulas of derivatives of inverse hyperbolic functions using implicit differentiation method.
Derivative of Arcsinhx
Assume arcsinhx = y, then we have x = sinh y. Now, differentiating both sides of x = sinh y with respect to x, we have:
dx/dx = d(sinh y)/dx
⇒ 1 = cosh y × dy/dx --- [Because derivative of sinh y is cosh y]
⇒ dy/dx = 1/coshy
= 1/√(1 + sinh2y) --- [Because cosh2A - sinh2A = 1 which implies coshA = √(1 + sinh2A)]
= 1/√(1 + x2) --- [Because x = sinh y]
⇒ d(arcsinhx)/dx = 1/√(1 + x2)
Derivative of Arccoshx
To find the derivative of arccoshx, we assume arccoshx = y. This implies we have x = cosh y. Now, differentiating both sides of x = cosh y, we have
dx/dx = d(cosh y)/dx
⇒ 1 = sinh y × dy/dx --- [Because derivative of cosh y is sinh y]
⇒ dy/dx = 1/sinhy
= 1/√(cosh2y - 1) --- [Because cosh2A - sinh2A = 1 which implies sinhA = √(cosh2A - 1)]
= 1/√(x2 - 1) --- [Because x = cosh y]
⇒ d(arccoshx)/dx = 1/√(x2 - 1), x > 1
Derivative of Arctanhx
Next, we will calculate the derivative of tanhx. Assume arctanhx = y, then we have x = tanh y. Now, differentiating both sides of x = tanh y with respect to x, we have
dx/dx = d(tanh y)/dx
⇒ 1 = sech2y × dy/dx --- [Because derivative of tanh y is sech2y]
⇒ dy/dx = 1/sech2y
= 1/(1 - tanh2y) --- [Using hyperbolic trig identity 1 - tanh2A = sech2A]
= 1/(1 - x2) --- [Because x = tanhy]
⇒ d(arctanhx)/dx = 1/(1 - x2), |x| < 1
Derivative of Arccothx
We will find the derivative of arccothx using a similar way as we did for the derivative of arctanhx. Assume arccothx = y, then we have x = coth y. Now, differentiating both sides of x = coth y with respect to x, we have
dx/dx = d(coth y)/dx
⇒ 1 = -csch2y × dy/dx --- [Because derivative of coth y is -csch2y]
⇒ dy/dx = -1/csch2y
= -1/(coth2y - 1) --- [Using hyperbolic trig identity coth2A - 1 = csch2A]
= -1/(x2 - 1) --- [Because x = cothy]
⇒ d(arccothx)/dx = -1/(x2 - 1) , |x| > 1
Derivative of Arcsechx
To find the derivative of arcsechx, we will use the formula for the derivative of sechx. Assume arcsechx = y, this implies we have x = sech y. Now, differentiating both sides of x = sech y with respect to x, we have
dx/dx = d(sech y)/dx
⇒ 1 = -sech y tanh y × dy/dx --- [Because derivative of sech y is -sech y tanh y]
⇒ dy/dx = -1/sech y tanh y
= -1/sech y √(1 - sech2y) --- [Using hyperbolic trig identity 1 - tanh2A = sech2A which implies tanh A = √(1 - sech2A)]
= -1/x √(1 - x2)
⇒ d(arcsechx)/dx = -1/x √(1 - x2) , 0 < x < 1
Derivative of Arccschx
To find the derivative of arccschx, we will use the formula for the derivative of cschx. Assume arccschx = y, this implies we have x = csch y. Now, differentiating both sides of x = csch y with respect to x, we have
dx/dx = d(csch y)/dx
⇒ 1 = -csch y coth y × dy/dx --- [Because derivative of sech y is -csch y coth y]
⇒ dy/dx = -1/csch y coth y
= -1/csch y √(csch2y + 1)--- [Using hyperbolic trig identity coth2A - 1 = csch2A which implies coth A = ±√(csch2A + 1)]
= -1/|x| √(x2 + 1)
⇒ d(arccschx)/dx = -1/|x| √(x2 + 1) , x ≠ 0
Derivatives of Hyperbolic Functions and Inverse Hyperbolic Functions Table
In the above sections, we have derived the formulas for the derivatives of hyperbolic functions and inverse hyperbolic functions. Let us now summarize all the derivatives in a table below along with their domains (restrictions):
Function | Derivative | Domain |
---|---|---|
sinhx | coshx | -∞ < x < ∞ |
coshx | sinhx | -∞ < x < ∞ |
tanhx | sech2x | -∞ < x < ∞ |
cothx | -csch2x | x ≠ 0 |
sechx | -sechx tanhx | -∞ < x < ∞ |
cschx | -cschx cothx | x ≠ 0 |
arcsinhx | 1/√(x2 + 1) | -∞ < x < ∞ |
arccoshx | 1/√(x2 - 1) | x > 1 |
arctanhx | 1/(1 - x2) | |x| < 1 |
arccothx | 1/(1 - x2) | |x| > 1 |
arcsechx | -1/x√(1 - x2) | 0 < x < 1 |
arccschx | -1/|x|√(1 - x2) | x ≠ 0 |
Important Notes on Derivative of Hyperbolic Functions
- d(sinhx)/dx = coshx
- d(coshx)/dx = sinhx
- d(tanhx)/dx = sech2x
- d(cothx)/dx = -csch2x (x ≠ 0)
- d(sechx)/dx = -sechx tanhx
- d(cschx)/dx = -cschx cothx (x ≠ 0)
☛ Related Topics:
Derivatives of Hyperbolic Functions Examples
-
Example 1: Find the derivative of hyperbolic function f(x) = sinhx + 2coshx
Solution: To find the derivative of f(x) = sinhx + 2coshx, we will use the following formulas:
- d(sinhx)/dx = coshx
- d(coshx)/dx = sinhx
We have
d(sinhx + 2coshx)/dx = d(sinhx)/dx + d(2coshx)/dx
= coshx + 2sinhx
Answer: Derivative of sinhx + 2coshx is equal to coshx + 2sinhx.
-
Example 2: Calculate the derivative of f(x) = 2x5tanhx.
Solution: To find the derivative of f(x) = 2x5tanhx, we will use the product rule, power rule and formula for the derivative of hyperbolic function tanhx.
d(2x5tanhx)/dx = 2 [ (x5)' tanhx + x5 (tanhx)' ]
= 2[5x4 tanhx + x5 sech2x]
= 2x4 (5 tanhx + x sech2x)
Answer: The derivative of f(x) = 2x5tanhx is 2x4 (5 tanhx + x sech2x).
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Example 3: Find the derivative of sinh x / (x + 1).
Solution: We will use the quotient rule to find this derivative. We know that derivative of hyperbolic function sinhx is equal to coshx. So, we have
d[sinh x / (x + 1)] / dx = [(sinh x)' (x + 1) - sinhx (x + 1)'] / (x + 1)2
= [coshx (x + 1) - sinhx] / (x + 1)2
Answer: Derivative of sinh x / (x + 1) is equal to [coshx (x + 1) - sinhx] / (x + 1)2
FAQs on Derivative of Hyperbolic Functions
What are Derivatives of Hyperbolic Functions?
The derivative of hyperbolic functions gives the rate of change in the hyperbolic functions as differentiation of a function determines the rate of change in function with respect to the variable. We have six main hyperbolic functions given by, sinhx, coshx, tanhx, sechx, cothx, and cschx.
What is the Derivative of Hyperbolic Functions Formula?
Given below are the formulas for the derivative of hyperbolic functions:
- Derivative of Sinhx: d(sinhx)/dx = coshx
- Derivative of Coshx: d(coshx)/dx = sinhx
- Derivative of Tanhx: d(tanhx)/dx = sech2x
- Derivative of Cothx: d(cothx)/dx = -csch2x (x ≠ 0)
- Derivative of Sechx: d(sechx)/dx = -sechx tanhx
- Derivative of Cschx: d(cschx)/dx = -cschx cothx (x ≠ 0)
How to Prove Derivatives of Hyperbolic Functions?
We can prove the derivative of hyperbolic functions by using the derivative of exponential function along with other hyperbolic formulas and identities. We know that hyperbolic functions are expressed as combinations of ex and e-x.
What are Derivatives of Inverse Hyperbolic Functions?
The derivatives of inverse hyperbolic functions are given by:
- Derivative of arcsinhx: d(arcsinhx)/dx = 1/√(x2 + 1), -∞ < x < ∞
- Derivative of arccoshx: d(arccoshx)/dx = 1/√(x2 - 1), x > 1
- Derivative of arctanhx: d(arctanhx)/dx = 1/(1 - x2), |x| < 1
- Derivative of arccothx: d(arccothx)/dx = 1/(1 - x2), |x| > 1
- Derivative of arcsechx: d(arcsechx)/dx = -1/x√(1 - x2), 0 < x < 1
- Derivative of arccschx: d(arccschx)/dx = -1/|x|√(1 + x2), x ≠ 0
How Do You Take the Derivative of Hyperbolic Function Sinx?
We can find the derivative of sinhx by expressing it as d(sinhx)/dx = (ex - e-x)/2. So, we have d(sinhx)/dx = d[(ex - e-x)/2] / dx = (ex + e-x)/2 = cosh x.
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