Question

Solve:____________
4cos36° -4sin54°-4​

Answer 1

Take out 4 common

4(cos36°-sin54°-1)

Now we know that Sin(90-x)=Cosx

Sin(90-36)=sin54

4(cos36°-Sin(90-36)-1)

4(cos36°-cos36°-1)

4(1)→4

Answer:-

4

Answer 2

Answer:

$→\sin(90° - \theta) = \cos( \theta) \\ →\cos(90 °- \theta) = \sin( \theta) \\→ 4 \cos(36°) - 4 \sin(54°) - 4 \\ = 4 \cos(36°) - 4 \ \sin(90° -36° ) - 4 \\ = 4 \cos(36°) - 4 \cos(36°) - 4 \\ = \boxed{ - 4}$

• -4 is the right answer.