How to find local max and min points for y = sinxcox^3x

In summary, the conversation is about finding the local max and min points for the function y = sinxcox3x. The approach involves finding the first and second derivatives and solving for the values of x when the first derivative is equal to 0. The process of finding the derivatives is discussed and the values for one of the equations are solved.
  • #1
cruisx
39
0

Homework Statement



Hey, so i need some help trying to find the local max and min points for y = sinxcox3x

Homework Equations



The Attempt at a Solution


I know i need to find the first and 2nd derivative but i do not know if i am doing it right. I also do not know what to do after wards.

my first derivative ends up being cos^2x(cos^2x - 3sin^2x)
what do i do after this to solve my question. Help would be appreciated.
 
Last edited:
Physics news on Phys.org
  • #2
You need to find the first derivative and check the values of x when Dy = 0 - so set your derivative to 0 and solve for x.
I did not check your derivative. Did you apply the product rule?
 
  • #3
I got the same derivative.
 
  • #4
Yes my derivative is cos^2x(cos^2x - 3sin^2x) so do i do

0 = cos^2x or 0 =cos^2x - 3sin^2x)

and solve for both?
 
  • #5
Yup you solve both
 
  • #6
VeeEight said:
Yup you solve both

Ok so i got the values for the left but the right eqn is nto going well. I do not understand what to do after cos^2x - 3(1-cos^2x)
 
  • #7
cruisx said:
Ok so i got the values for the left but the right eqn is nto going well. I do not understand what to do after cos^2x - 3(1-cos^2x)
[itex]cos^2 x- 3 sin^2 x[/itex][itex]= cos^2 x- 3(1- cos^2 x)[/itex][itex]= cos^2 x- 3+ 3cos^2 x= 0[/itex]
so [itex]4cos^2 x= 3[/itex], [itex]cos^2(x)= 3/4[/itex].
 

Related to How to find local max and min points for y = sinxcox^3x

What is the equation for finding local max and min points for y = sinxcox^3x?

The equation for finding local max and min points for y = sinxcox^3x is to first take the derivative of the function, set it equal to 0, and then solve for x. The x-values obtained from this process will be the local max and min points.

How do I take the derivative of y = sinxcox^3x?

To take the derivative of y = sinxcox^3x, you will need to use the product rule and the chain rule. The derivative will be 3cosxsin^2x + cos^3xsinx.

Are there any specific steps I need to follow when solving for x in the derivative equation?

Yes, there are specific steps you should follow to solve for x in the derivative equation. First, factor out any common terms. Then, use the quadratic formula to solve for x. Finally, check your answer by plugging it back into the original equation.

Can I use a graphing calculator to find local max and min points for y = sinxcox^3x?

Yes, you can use a graphing calculator to find local max and min points for y = sinxcox^3x. Simply enter the equation into the calculator and use the "zero" or "root" function to find the x-values where the derivative is equal to 0.

What do the local max and min points represent in the graph of y = sinxcox^3x?

The local max and min points represent the highest and lowest points on the curve of the graph of y = sinxcox^3x, respectively. They are also known as turning points, where the direction of the curve changes from increasing to decreasing or vice versa.

Similar threads

  • Calculus and Beyond Homework Help
Replies
6
Views
1K
  • Calculus and Beyond Homework Help
2
Replies
36
Views
4K
  • Calculus and Beyond Homework Help
Replies
5
Views
955
Replies
2
Views
1K
  • Calculus and Beyond Homework Help
Replies
1
Views
1K
  • Calculus and Beyond Homework Help
Replies
4
Views
1K
  • Calculus and Beyond Homework Help
Replies
30
Views
2K
  • Calculus and Beyond Homework Help
Replies
25
Views
484
  • Calculus and Beyond Homework Help
Replies
2
Views
1K
  • Calculus and Beyond Homework Help
Replies
6
Views
886
Back
Top