March 27th, 2017, 10:59 AM  #1 
Newbie Joined: Mar 2017 From: Netherlands Posts: 11 Thanks: 0  Calculable tan(ϕ)
Hi, Who can help me to sum below? I can not get them on. Given is the function : f(x)= 2cos(x) with Df = [0, π ] Calculate tan(ϕ) as (ϕ) the size of the angle which is where the graph of f (x) intersects the Xaxis 
March 27th, 2017, 11:28 AM  #2  
Math Team Joined: Jul 2011 From: Texas Posts: 2,770 Thanks: 1424  Quote:
$\tan{\phi} = f'\left(\dfrac{\pi}{2}\right)$  
March 27th, 2017, 09:43 PM  #3 
Newbie Joined: Mar 2017 From: Netherlands Posts: 11 Thanks: 0  
March 28th, 2017, 05:24 AM  #4 
Math Team Joined: Jul 2011 From: Texas Posts: 2,770 Thanks: 1424 
$\phi = \arctan(2)$
