Trigonometric Equations Question 221
Question: In $ \Delta ABC $ , if $ a=3,b=4,c=5 $ , then $ \sin 2B= $
[MP PET 1983]
Options:
A) 4/5
B) 3/20
C) 24/25
D) 1/50
Show Answer
Answer:
Correct Answer: C
Solution:
- $ \cos B=\frac{9+25-16}{2.3.5}=\frac{18}{2.3.5}=\frac{3}{5}\Rightarrow \sin B=\frac{4}{5} $ Therefore $ \sin 2B=2.\frac{4}{5}.\frac{3}{5}=\frac{24}{25} $ .
BETA
