Cos6 . Cos42 . Cos66 . Cos78=?

At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.

Get our expert's

answer on brainly

SEE EXPERT ANSWER

Get your free account and access expert answers to this and thousands of other questions.

A community for students.

Cos6 . Cos42 . Cos66 . Cos78=?

Mathematics
See more answers at brainly.com
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.

Get this expert

answer on brainly

SEE EXPERT ANSWER

Get your free account and access expert answers to this and thousands of other questions

just trying.. cos 6 = sin 84 = 2sin 42 cos 42....
(78-66) /2 =6 so maybe 2 cos C cos D formula...
(cos 6) (cos 42)(cos 66) (cos 78) = (1/4) * (cos72 + cos60) * (cos120 + cos36) = (1/4) (cos72 + 1/2) * (- 1/2 + cos36) =(1/4)( cos 72 cos36 + 1/2( cos 36- cos72) -1/4 ) use formula for cos a- cos b , = 1/4 ( 2 sin54 sin18 -1/4) =1/4 ( sin36 sin54/ cos 18 -1/4) = 1/4( cos 18 - cos 90) / 2cos18 -1/4) = ans this might seem tedious to read at first, but i believe 've done it correctly.. please reply..

Not the answer you are looking for?

Search for more explanations.

Ask your own question

Other answers:

are u sure u typed the qustion properly? isn't there any + or _ sign
Nah..! Question is Correct
i think i got it :) use the formula this : -------------------------------------------- cos(a) . cos(60-a) . cos(60+a) = [cos(3a)]/4 ------------------------------------------- set a = 6 cos(6) . cos(54) . cos(66) = cos(18)/4 so, cos(6) . cos(66) = cos(18)/(4 * cos(54)) .... (1) set a = 18 cos(18) . cos(42) . cos(78) = cos(54)/4 so, cos(42) . cos(78) = cos(54)/(4 . cos(18)) .... (2) multiply both, giving us : cos(6) cos(42) cos(66) cos(78) = 1/16 * cos(18)cos54/(cos(18)*cos(54) = 1/16 * 1 = 1/16
Yup...Thats Correct...thxx.)
welcome, :)
even my ans yielded 1/16 ! voila! seems i complicated it too much! :P

Not the answer you are looking for?

Search for more explanations.

Ask your own question