Does $sin^2theta-cos^2theta=1-2sin^2theta$ ?

Question

4012 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-05-12T04:47:08

$"No"$
$"Almost :"$
$sin^2(theta) - cos^2(theta) = 2 sin^2(theta) - 1$

$sin^2(theta) + cos^2(theta) = 1$

$=> sin^2(theta) - cos^2(theta)$
$= sin^2(theta) - (1 - sin^2(theta))$
$= 2 sin^2(theta) - 1$

Answer 2 · 2018-05-12T04:49:02

No that would be equal to $2sin^2theta-1$

Since $cos^2theta=1-sin^2theta$
Putting the value $cos^2theta$ in original equation we get
$2sin^2theta-1$

Does sin^2theta-cos^2theta=1-2sin^2thetasin^2theta-cos^2theta=1-2sin^2theta?