Question

3 cos 72 -4 sin 18
pls solve this as fast as possible ​

Answer 1

Answer:

Step-by-step explanation:

cos 72 = sin 18          since cos(90-72)=sin 18

3*sin 18 - 4*sin 18= - sin 18

- sin 18 = - 0.3090

Answer 2

. root5-1

cos72= ——-—— =sin18

4

=3(root5-1/4)-4(root5-1/4)

=3root5-3.

————— —(root 5-1)

4

LCM is 4

1-root5

= ————

4

hope it helps u