InterviewSolution
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The value of \(\frac{{\cos \,{{29}^ \circ }\cos ec\,{{61}^ \circ }\tan \,{{45}^ \circ } + 2\sin \,{{35}^ \circ }\sec \,{{55}^ \circ }}}{{3{{\sin }^2}\,{{42}^ \circ } + 3{{\sin }^2}\,{{48}^ \circ }}}\) is: |
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Answer» Correct Answer - Option 2 : 1 Given: \(\frac{{\cos \,{{29}^ \circ }\cos ec\,{{61}^ \circ }\tan \,{{45}^ \circ } + 2\sin \,{{35}^ \circ }\sec \,{{55}^ \circ }}}{{3{{\sin }^2}\,{{42}^ \circ } + 3{{\sin }^2}\,{{48}^ \circ }}}\) Trigonometry properties: cosecθ = 1/sinθ sin(90 – θ ) = cosθ secθ = 1/cosθ cos(90 – θ ) = sinθ sin2θ + cos2θ = 1 tan 45o = 1 Calculation: \(\frac{{\cos \,{{29}^ \circ }\cos ec\,{{61}^ \circ }\tan \,{{45}^ \circ } + 2\sin \,{{35}^ \circ }\sec \,{{55}^ \circ }}}{{3{{\sin }^2}\,{{42}^ \circ } + 3{{\sin }^2}\,{{48}^ \circ }}}\) According to the trigonometry properties ⇒ {cos 29o (1/sin 61o) tan 45o + 2 sin 35o (1/cos 55o)}/ 3sin2 42o + 3sin2(90o – 48o) ⇒ {(cos 29o/cos61o)tan 45o + 2 sin 35o/cos 55o}/3(sin 42o + cos42o) ⇒ {(cos29o/sin(90 o – 61o))× 1 + 2 sin 35o/cos(90o – 55o)}/3 × 1 ⇒ {cos 292/cos 292 + 2 sin 35o/sin 35o}/3 ⇒ (1 + 2)/3 ⇒ 1 ∴ The value of \(\frac{{\cos \,{{29}^ \circ }\cos ec\,{{61}^ \circ }\tan \,{{45}^ \circ } + 2\sin \,{{35}^ \circ }\sec \,{{55}^ \circ }}}{{3{{\sin }^2}\,{{42}^ \circ } + 3{{\sin }^2}\,{{48}^ \circ }}}\) is 1. |
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