(sinθ-cosθ)²=sin²θ+cos²θ-2sinθcosθ=1-2sinθcosθ=1/25;2sinθcosθ=24/25;sinθcosθ=12/25;∴sin^4θ+cos^4θ=(sin²θ+cos²θ)²-2sin²θcos²θ=1²-2×(12/2...