हिंदी

Evaluate the following: 5 cot 5 ° cot 15 ° cot 25 ° cot 35 ° cot 45 ° 7 tan 45 ° tan 55 ° tan 65 ° tan 75 ° tan 85 ° + 2 cosec 12 ° cosec 24 ° cos 78 ° cos 66 ° 7 sin 14 ° sin 23 ° sec 76 ° sec 67 ° - Mathematics

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प्रश्न

Evaluate the following: `(5cot5° cot15° cot25° cot35° cot45°)/(7tan45° tan55° tan65° tan75° tan85°) + (2"cosec"12° "cosec"24° cos78° cos66°)/(7sin14° sin23° sec76° sec67°)`

योग

उत्तर

`(5cot5° cot15° cot25° cot35° cot45°)/(7tan45° tan55° tan65° tan75° tan85°) + (2"cosec"12° "cosec"24° cos78° cos66°)/(7sin14° sin23° sec76° sec67°)`


= `(5cot(90° - 85°) cot(90° - 75°) cot(90° - 65°) cot(90° - 55°) xx 1)/(7 xx 1xx tan55° tan65° tan75° tan85°) + (2"cosec"(90° - 78°) "cosec"(90° - 66°) cos78° cos66°)/(7sin(90° - 76°) sin(90° - 67°) sec76° sec67°)`

 

= `(5tan85° tan75° tan65° tan55°)/(7 xx tan55° tan65° tan75° tan85°) + (2sec78° sec66° xx 1/(sec78°) xx 1/(sec66°))/(7cos76° cos67° xx 1/(cos76°) xx 1/(cos67°)`


= `(5)/(7) + (2)/(7)`

= `(7)/(7)`
= 1.

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Trigonometric Equation Problem and Solution
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 27: Trigonometrical Ratios of Standard Angles - Exercise 27.3

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फ्रैंक Mathematics [English] Class 9 ICSE
अध्याय 27 Trigonometrical Ratios of Standard Angles
Exercise 27.3 | Q 5.1
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