C-09-Q188mediumsingle_mcqSolve: sinθ+cosθ=1\sin\theta + \cos\theta = 1sinθ+cosθ=1, 0∘≤θ≤90∘0^\circ \le \theta \le 90^\circ0∘≤θ≤90∘. θ=?\theta = ?θ=?aonly 0∘0^\circ0∘bonly 90∘90^\circ90∘c0∘0^\circ0∘ or 90∘90^\circ90∘d30∘30^\circ30∘ব্যাখ্যাSquaring gives 1+2sinθcosθ=11+2\sin\theta\cos\theta=11+2sinθcosθ=1, so sinθcosθ=0\sin\theta\cos\theta=0sinθcosθ=0. Within [0∘,90∘][0^\circ,90^\circ][0∘,90∘] this holds at both endpoints, giving θ=0∘\theta=0^\circθ=0∘ or 90∘90^\circ90∘.