Recent content by niceperson

Used z=x+t get: int(1/(cosz+1)=in(t) on separation of the variables. cheers

we could use complex numbers (de moivres theorem) here and express sin^5x, sin^3x in terms of sin5x, sin3x (directly integratable)

Homework Statement solve the differential eqn: dx/dt=cos(x+t) Homework Equations The Attempt at a Solution x'=cos(x+t)=cosxcost-sinxsint let z=sinx, dz/dx=cosx dz/dt=(dz/dx).(dx/dt)=cosx(dx/dt) however this substitution quickly fails any ideas? thanksx

thanks dick does work!

Homework Statement solve: y'=(x+y-1)/(x-y-2) i.e Homework Equations The Attempt at a Solution let y=vx thus y'=v'x+v by substitution: v'x+v=(1+y/x-1/x)/(1-y/x-2/x)=(1+v-1/x)/(1-v-2/x) v'x=(1-1/x+v^2+2v/x)/(1-v-2/x) still can't separate the variables...any...