Prove the following trigonometric identities:
6.) sec(theta)/tan(theta)=csc(theta)

(3 different)
calculation | reason

Last year, laura had $30,000 to invest. she invested some of it in an account that paid 7% simple interest per year, and she invested the rest in an account that paid 8% simple interest per year. after one year, she received a total of $2230 in interest. how much did she invest in each account?