Q4 of 164 Page 44

Show that
sin (90° – θ)tan θ = sin θ

Simplifying the left hand side:

⇒ cos θ tan θ

⇒ cos θ (sin θ/cos θ)

⇒ sin θ

Which is equal to right hand side.

Hence proved.

Show that

cos 20° cos 70° – sin 70° sin 20° = 0

Show that

cos 20° cos 70° – sin 70° sin 20° = 0

Show that

sin (90° – θ)tan θ = sin θ

Show that

Show thatsin (90° – θ)tan θ = sin θ