Q72.If in a triangle ABC, b+c11 = c+a12 = a+b13 , then cos A is equal to (1) 5/7 (2) 1/5 (3) 35/19 (4) 19/35
What This Question Tests
Requires setting up proportions to find the ratios of the sides of a triangle and then applying the cosine rule to find the cosine of a specific angle.
Concepts Tested
Formulas Used
cos A = (b^2 + c^2 - a^2) / (2bc)
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π Question Details
- Chapter
- Trigonometric Functions & Equations
- Topic
- Cosine rule
- Year
- 2012
- Shift
- 12 May Online
- Q Number
- Q72
- Type
- MCQ
- NCERT Ref
- Class 11 Mathematics Ch 3: Trigonometric Functions
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