Answer :

Given: cos 9 = sin and 9<90° i.e. 9α is an acute angle

And we know that, sin(90°-θ) = cos θ by property.


So, we can write cosine in terms of sine using this property,


cos 9 = sin (90°-)


Thus, sin (90°-9) = sin (cos 9 = sin(90°-9) & sin(90°-) = sin )


90°-9 =


10 = 90° (By rearranging)


= 9°


We have got the value of i.e. = 9°


Putting it in tan 5, we get


tan 5 = tan (5.9) = tan 45° = 1


, tan 5 = 1

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Trigonometric IdentitiesTrigonometric IdentitiesTrigonometric Identities39 mins
Heights and Distances-IHeights and Distances-IHeights and Distances-I45 mins
Trigonometric Identities-IITrigonometric Identities-IITrigonometric Identities-II43 mins
Introduction to Linear Equations in Two VariablesIntroduction to Linear Equations in Two VariablesIntroduction to Linear Equations in Two Variables62 mins
Area Related to Circles- Important Formula and ConceptsArea Related to Circles- Important Formula and ConceptsArea Related to Circles- Important Formula and Concepts59 mins
Sphere and HemisphereSphere and HemisphereSphere and Hemisphere16 mins
Resources and Development RevisionResources and Development RevisionResources and Development Revision28 mins
Cube and CuboidCube and CuboidCube and Cuboid41 mins
History - Concept and QuestionsHistory - Concept and QuestionsHistory - Concept and Questions57 mins
Right Circular Cone And FrustumRight Circular Cone And FrustumRight Circular Cone And Frustum43 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
caricature
view all courses