Question

$\frac{sin70+cos50}{cos70+sin50}=$

• A. 1/√3
• B. √3
• C. 1/2
• D. 1

Answer 1

Answer:

B. √3

$sinA+sinB=2sin(\frac{A+B}{2})cos(\frac{A-B}{2})$

$\frac{sin70+cos50}{cos70+sin50}=\frac{2sin(\frac{70+50}{2})cos(\frac{70-50}{2})}{2cos(\frac{70+50}{2})cos(\frac{70-50}{2})}$

$=tan60$

$=\sqrt3$