Acounterexample for the expression sec^2x-1=cosx/cscx is 45 degrees true or false

Aswim teacher sells lesson packages. the best deal has the highest ratio of lessons to total cost.swim lesson packagesnumber of lessons total cost$10$4010 1 $8015$80which package is the best deal? l lesson for $105 lessons for $4010 lessons for $8015 lessons for $80mark this and returnsave and exit

Find dy/dx using implicit differentiation ln(20+e^xy)=y

Ineed with this problem 21 show steps