if y =arc tan (e^x) prove that dy/dx = 1/2 sin2y
shuning Member Joined Aug 23, 2008 Messages 654 Location Central Coast - Chatswood all the way :p Gender Male HSC 2009 Mar 23, 2009 #1 if y =arc tan (e^x) prove that dy/dx = 1/2 sin2y
D Drongoski Well-Known Member Joined Feb 22, 2009 Messages 4,253 Gender Male HSC N/A Mar 23, 2009 #2 shuning said: if y =arc tan (e^x) prove that dy/dx = 1/2 sin2y Click to expand... y = arctan (e^x) tan y = e^x d/dx both sides (implicitly): sec^2y dy/dx = e^x = tan y dy/dx = tan y/ sec^2 y = (sin y/cos y) x cos^2 y = sin y cos y = 1/2 (2 sin y cos y) = 1/2 sin 2y
shuning said: if y =arc tan (e^x) prove that dy/dx = 1/2 sin2y Click to expand... y = arctan (e^x) tan y = e^x d/dx both sides (implicitly): sec^2y dy/dx = e^x = tan y dy/dx = tan y/ sec^2 y = (sin y/cos y) x cos^2 y = sin y cos y = 1/2 (2 sin y cos y) = 1/2 sin 2y