Derivatives of trigonometric functions

In summary, the derivative formulas for the six basic trigonometric functions are: sin x = cos x, cos x = -sin x, tan x = sec^2 x, cot x = -csc^2 x, sec x = sec x * tan x, and csc x = -csc x * cot x. To use the chain rule to find derivatives of trigonometric functions, you must rewrite the function in terms of a single variable and then take the derivative of the outer function multiplied by the derivative of the inner function. The relationship between the derivatives of sine and cosine is that the derivative of cosine is equal to the negative derivative of sine. To find the derivative of a trigonometric function using the quotient
  • #1
Brunno
80
0

Homework Statement


I'm learning now about darivative all by my self (without a teacher) and I'm not sure about this development

Homework Equations







The Attempt at a Solution



[tex]Y=senx[/tex]

[tex]y+{\Delta}Y=sen(x+{\Delta}Y)[/tex]

[tex]{\Delta}Y=senx*cos{\Delta}x+ sen{\Delta}x*cosx[/tex]

What about this cos,what is it doing in the equation?
I really don't get it.
 
Physics news on Phys.org
  • #2


this comes from the double angle formula.

it says that: sin (A + B) = sinAcosB + sinBcosA

you can find the same thing for sin (x + dY)
 
  • #3


Oh,now I think i get it!
Thankyou!
 

1. What are the derivative formulas for the six basic trigonometric functions?

The derivative formulas for the six basic trigonometric functions are:

  • sin x = cos x
  • cos x = -sin x
  • tan x = sec^2 x
  • cot x = -csc^2 x
  • sec x = sec x * tan x
  • csc x = -csc x * cot x

2. How do you use the chain rule to find derivatives of trigonometric functions?

To use the chain rule to find derivatives of trigonometric functions, you must first rewrite the function in terms of a single variable. Then, take the derivative of the outer function and multiply it by the derivative of the inner function. For example, if you have the function f(x) = sin(3x), you would rewrite it as f(u) = sin(u) where u = 3x. Then, using the derivative formula for sin x, you would get f'(u) = cos(u) = cos(3x). Finally, multiply by the derivative of the inner function (3) to get the final answer: f'(x) = 3cos(3x).

3. What is the relationship between the derivatives of sine and cosine?

The relationship between the derivatives of sine and cosine is that the derivative of cosine is equal to the negative derivative of sine. In other words, the derivative of cosine is the negative of the derivative of sine. This relationship can be seen in the derivative formulas for sine and cosine: cos x = -sin x and sin x = cos x.

4. How do you find the derivative of a trigonometric function using the quotient rule?

To find the derivative of a trigonometric function using the quotient rule, you must first rewrite the function as a fraction. Then, apply the quotient rule, which states that the derivative of the numerator times the denominator minus the numerator times the derivative of the denominator, all divided by the denominator squared. For example, if you have the function f(x) = tan x / cos x, you would rewrite it as f(x) = tan x * cos^-1 x. Then, using the quotient rule, you would get f'(x) = (sec^2 x * cos x - tan x * -sin x) / cos^2 x = sec^2 x + tan x * sin x / cos^2 x.

5. What is the derivative of the inverse trigonometric functions?

The derivative of the inverse trigonometric functions is given by the formula: f'(x) = 1 / √(1 - x^2). This applies to the inverse sine, inverse cosine, and inverse tangent functions. The derivative of the inverse cotangent function is -1 / √(1 - x^2), and the derivative of the inverse secant and inverse cosecant functions is 1 / (|x| * √(x^2 - 1)).

Similar threads

  • Precalculus Mathematics Homework Help
Replies
6
Views
1K
  • Precalculus Mathematics Homework Help
Replies
14
Views
812
Replies
3
Views
1K
  • Precalculus Mathematics Homework Help
Replies
6
Views
2K
Replies
3
Views
582
  • Precalculus Mathematics Homework Help
Replies
6
Views
1K
  • Precalculus Mathematics Homework Help
Replies
12
Views
2K
Replies
28
Views
2K
Replies
1
Views
805
  • Precalculus Mathematics Homework Help
Replies
9
Views
2K
Back
Top