Asample of a compound made up of various elements totals 90 ounces. if the total amount of lead in the compound weighs 23 ounces, what percentage of the compound is made up of lead? if necessary, round your answer to the nearest hundredth of a percent.

Which sum or difference identity would you use to verify that cos (180° - q) = -cos q? a.) sin (a -b) = sin a cos b – cos a sin b b.) cos (a -b) = cos a cos b – sin a sin b c.) cos (a -b) = cos a cosb + sin a sin b d.) sin (a + b) = sin a cos b + cos a sin b