Question

cos 10 ° + cos 20 °+ ...cos 80 ° please find it and I'll mark the correct one as brainliest...​

Answer 1

Answer:

40

Step-by-step explanation:

Cos 10° + cos 20°........ Cos 80°

Since Cos 80° can be written as Sin 10°

Similarly all the other Cos theta degrees will get converted to Sin theta degrees after Cos 40°

Therefore

Cos 10° + Sin 10° = 1

So 40 will be the answer.

Answer 2

Answer:

is their nothing between cos20 and cos80