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:

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)}/ 3sin42o + 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.



Discussion

No Comment Found

Related InterviewSolutions