Posted by **sh** on Sunday, December 5, 2010 at 4:15pm.

Find the interval(s) where the function is increasing where and it is decreasing.

f(x)=sin(x+(pi/2)) for 0≤x≤2pi

so my derivative is f'(x)=cos(x+(pi/2))?

and my critical number is -pi/2?

- Calculus -
**Damon**, Sunday, December 5, 2010 at 5:04pm
cosine is positive for x +pi/2 = 0 to pi/2 and from 3 pi/2 to 2 pi

when x+pi/2 = 0 then x = -pi/2 or 3pi/2

when x + pi/2 = pi/2, x = 0

so one interval is x = 3pi/2 to 0

when x+pi/2 = 3 pi/2 then x = pi

when x+pi/2 = 2 pi then x = 3 pi/2

so second interval is frm x = pi to 3 pi/2

so finally the entire interval from x = pi to x = 2 pi (which is 0) has a positive derivative, function increasing

- Calculus -
**sh**, Sunday, December 5, 2010 at 5:19pm
Wow, so confusing. Thanks!

- Calculus -
**sh**, Sunday, December 5, 2010 at 5:24pm
So the whole interval is increasing? The function of cosx has a section of decreasing though.

## Answer this Question

## Related Questions

- PRE - CALCULUS - Eliminate the parameter t. Find a rectangular equation for the ...
- Trig - On the same set of axes, sketch and label the graphs of the equations y...
- Pre Calculus - sec x = -2 , π ≤ x ≤ 3π Use a calculator to...
- Please check my Calculus - 1. Given f(x)=-6/x, choose the correct statement A. ...
- algebra 1 help please - 4) a student score is 83 and 91 on her first two quizzes...
- cal 1 - f(x)= (1-sinx) interval (0≤x≤2π) find where the ...
- calculus - Given f(x)=sin(x)-2cos(x) on the interval [0,2pi]. a) Determine where...
- calc - i did this problem and it isn't working out, so i think i'm either making...
- Math/Trigonometry - 1. Solve: 2 cosē x - 3 cos x + 1 = 0 for 0 ≤ x < ...
- Grade 12 Calculus - Determine the absolute extrema of each function on the ...

More Related Questions