What is the minimum value of `(sin^2theta+cos^4theta)`?

Explanation

Let ` P =sin^2theta + cos^4theta`

`=> P = sin^2theta +(1-sin^2theta)^2`

`=> P = sin^2theta+1+sin^4 theta -2sin^2theta`

`=> P = sin^4theta - sin^2theta +1`

`=>P = 1+ sin^2theta(sin^2theta - 1)`

`=>P = 1- sin^2theta(1 - sin^2theta)`

`=>P = 1- sin^2thetacos^2theta`

`=>P = 1-(sin2theta)^2/4`

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