Question

Question #86fbc

Answer 1

Use trig identity:
`(1 + tan^2 t) = sec^2 t`
Develop the Left Side:
`LS = sin t (1 + tan^2 t) = sin t.sec^2 t = sin t/(cos^2 t)`
`LS = ((1)/(cos t))((sin t)/(cos t)) = sec t.tan t`. Proved