Question

What is the value of sin 12 - cos 78​

Answer 1

Answer:

0.

Step-by-step explanation:

sin 12 = cos(90 - 12)  = cos 78 so the answer is 0.

Answer 2

Answer:

0

Step-by-step explanation:

$\sin(12\º) - \cos(78\º)$

Consider the cofunction identity:

$\boxed{\sin(\theta)=\cos \left(\frac{\pi}{2} - \theta \right)}$

$\boxed{\sin(\theta)=\cos \left(90\º - \theta \right)}$

$\sin(12\º)=\cos(90\º - 12\º)=\cos(78\º)$

$\therefore \cos(78\º) - \cos(78\º) = 0$