Question Number 10480 by ssparasmani@gmail.com last updated on 13/Feb/17

d/dx(cos ^2 xdy/dx)=0

Answered by mrW1 last updated on 13/Feb/17

d/dx(cos ^2 xdy/dx)=0  ⇒cos ^2 xdy/dx=C_1   dy/dx=(C_1 /(cos^2  x))  ⇒y=∫(C_1 /(cos^2  x))dx=C_1 tan x+C_2

Answered by robocop last updated on 14/Feb/17

((cos^2 x)dy)/dx  ((1−sen^2 x)dy/dx  dy/dx−(sen^2 x)dy/dx  1−2senxcosx    d(1)/dx−d(2senxcosx)/dx=0  −2(senx(−senx)+cos^2 x=0  2sen^2 x−2cos^2 x=0  2−4cos^2 x=0  2cos^2 x=1  cosx=0.71  x=0.78