AP EAMCET2003MathematicsTrigonometric Equations
If A+B+C=270^ , then 2 A+ 2 B+ 2 C is equal to :
Options
- A4 A B C
- B4 A B C
- C1-4 A B C
- D1-4 A B C
Correct answer
C. 1-4 A B C
Step-by-step solution
2 A+ 2 B+ 2 C=2 (A+B) (A-B)+1-2 ^2 C=2 ( 3 2 -C ) (A-B)+1-2 ^2 C [ A+B+C=270^ B+C= 3 2 -C =1-2 C[ (A-B)+ C]=1-2 C[ (A-B)- (A+B)]=1-4 A B C