trigonometry

Question

<div>If sin^4 x-sin^2 x=1,then prove that tan^4 x-tan^2 x=1</div>

Answer 1

let y = sin^2(x)

then y^2 -y -1 = 0

y = 1/2 + or - .5sqr(1+4) = .5+/-.5sqr5

y = about -.618 ignore -sqr as square of any number is positive

y = sin^2(x) = 1.618

sinx = 1.272 which is impossible as all sines are between -1 and 1

arcsin(1.272) is undefined

No real solution

DNE

Null set