LIVE Course for free

Rated by 1 million+ students
Get app now
0 votes
12 views
in Aptitude by (30.0k points)
closed by

If SinA = 12/13, then find the value of 3Sin2A + 4Cos2A + 10


1. 13/169
2. 2222/169
3. 222/169
4. 13

1 Answer

0 votes
by (54.3k points)
selected by
 
Best answer
Correct Answer - Option 2 : 2222/169

Given:

SinA = 12/13.

Calculation:

In a right-angled triangle XYZ,

⇒ ∠XŶZ = 90° 

⇒ sinA = XY/XZ = 12/13, cosA = YZ/XZ = ?

According to Pythagoras theorem,

⇒ XY2 + YZ2 = XZ2.

⇒ 122 + YZ2 = 132

⇒ YZ2 = 169 - 144 = 25

⇒ YZ = 5.

Now, CosA = 5/13

According to question,

⇒ 3Sin2A + 4Cos2A + 10

⇒ 3 × (12/13)2 + 4 × (5/13)2 + 10

⇒ 3 × 144/169 + 4 × 25/169 + 10

Here, LCM of 169,1 is 169.

Now, (432 + 100 + 1690)/169

2222/169.

∴The value of 3sin2A + 4cos2A + 10 is 2222/169.

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...