Question

How would you solve these? i've gotten up to 2tanx+1-tan^2 x=0 for the first one but i don't know what else to do.
sin2x+cos2x=0
3sinx=1+cos2x
sqrt { 2 } sinx= cot x

Answer 1

let tan x = z
tan^2 x = z^2

solve the quadratic

Answer 2

oh thanks, but how abt the other ones?

Answer 3

for the second one use cos(2u)= 1 − 2 sin^2(u)