Question

Question #98a20

Answer 1

`sin (15^@20')=cos (74^@40')`.

Explanation:

We know that, `sin theta=cos (90^@- theta)`

`:. sin (15^@20')=cos (90^@-15^@20')`

Recall that, `1^@=60'`, so, we can say that, `90^@=89^@60'`.

`:. (90^@-15^@20')=(89^@60'-15^@20')`

`=74^@40'`

Therefore, `sin (15^@20')=cos (74^@40')`.