Question

maximum and minimum of y = cos(x) + sin (x)on the interval [0,2pi]

Answers

MathMate
Let
f(x) = cos(x) + sin (x)
Calculate derivative f'(x) and equate to zero. Solve for x.
For each value x1 of the solution, verify
f''(x). f''(x)<0 = maximum, and f''(x)>0 = minimum.
There may be multiple maxima and minima, choose the extreme values.
Tom
would the max be sqrt(2) at x = pi/4, and the min be -sqrt(2) at x = 5pi/4?
MathMate
Exactly! where tan(x)=1.
Tom
thank you very much
MathMate
You're welcome!

Related Questions