Express cot 85° + cos 75° in terms of trigonometric ratios of angles between 0° and 45°
NCERT Class X
Mathematics - Mathematics
Chapter _INTRODUCTION TO
TRIGONOMETRY
Answers
Answered by
164
Given :
Cot 85°+Cos75°
Formula used:
[cot(90°-thetha)=tan thetha &
cos(90°-thetha)= sin thetha]
cot(90°-5°)+cos(90°-15°)
tan 5° + sin 15°
Answer is :
tan 5° + sin 15°
Cot 85°+Cos75°
Formula used:
[cot(90°-thetha)=tan thetha &
cos(90°-thetha)= sin thetha]
cot(90°-5°)+cos(90°-15°)
tan 5° + sin 15°
Answer is :
tan 5° + sin 15°
Answered by
90
We know, cos θ = sin (90° - θ) and cot θ = tan (90° - θ)
Applying these two formulae, we get the folllowing:-
cot 85° + cos 75°
= tan (90°- 5°) + sin(90°- 15°)
= tan 5° + sin 15°
Applying these two formulae, we get the folllowing:-
cot 85° + cos 75°
= tan (90°- 5°) + sin(90°- 15°)
= tan 5° + sin 15°
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