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If sin⁡(θ)−cos⁡(θ)=0\sin (θ) - \cos (θ) = 0, the value of sin4 (θ) + cos4 (θ) is:

Solution

✅ Correct Option: 2

If sin⁡(θ)−cos⁡(θ)=0\sin(\theta) - \cos(\theta) = 0

Then sin⁡(θ)=cos⁡(θ)\sin(\theta) = \cos(\theta)

Since sin⁡2(θ)+cos⁡2(θ)=1\sin^2(\theta) + \cos^2(\theta) = 1

And sin⁡(θ)=cos⁡(θ)\sin(\theta) = \cos(\theta)

Therefore 2sin⁡2(θ)=12\sin^2(\theta) = 1

So sin⁡2(θ)=12\sin^2(\theta) = \frac{1}{2} and cos⁡2(θ)=12\cos^2(\theta) = \frac{1}{2}

Now, sin⁡4(θ)+cos⁡4(θ)\sin^4(\theta) + \cos^4(\theta)

=(12)2+(12)2= (\frac{1}{2})^2 + (\frac{1}{2})^2

=14+14= \frac{1}{4} + \frac{1}{4}

=12= \frac{1}{2}

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