Question

plzzzzz ans my que..
I have exam today​

Answer 1

cos 12°-sin 78°

= cos (90-78)°-sin78°

= sin 78° -sin 78°

= 0

then answer will be zero.

if you agree with mark the brainliest my answer.

Answer 2

cos12 - sin78

now

cos(78+12)=cos78cos12 - sin78 sin12__________(1)

tan78=tan12

so

sin78/cos78=sin12/cos12

sin78/cos12=sin12/cos78

let ratio be x

sin78=cos12*x

sin12=cos78*x

put value in ______(1)

cos78 cos12 - x^2cos12cos78=0

(1-x^2)cos78cos12=0

x=plus 1and -1

so

when x=1

sin78=cos12

and the value is 0

now at x=-1

sin78=cos12

so

from( 1)

sin^2(12)-cos^2(78)=0

sin 12 -cos 78=0(ans)

sin12 +cos 78=0

0 is the and one more but now I can't solve without copy