Comment on Activity 5
`tan^2 theta + 1
`
`= (sin^2 theta)/(cos^2 theta)+1`
`=(sin^2 theta+cos^2 theta)/(cos^2 theta)`
`=1/(cos^2 theta)`
`=(1/(cos theta))^2`
`=sec^2 theta`
Be sure you know a reason for each step in this calculation.