Page 4 - Trigonometry

Relation between Trigonometric Ratios
• cosec θ =1/sin θ

• sec θ = 1/cos θ

• tan θ = sin θ/cos θ

• cot θ = cos θ/sin θ=1/tan θ

Trigonometric Ratios of Specific Angles
Range of Trigonometric Ratios from 0 to 90 degrees

For 0 ≤ θ ≤ 90 ,
∘
∘
• 0 ≤ sinθ ≤ 1

• 0 ≤ cosθ ≤ 1
• 0 ≤ tanθ < ∞

• 1 ≤ secθ < ∞

• 0 ≤ cotθ < ∞

• 1 ≤ cosecθ < ∞
tanθ and secθ are not defined at 90 .
∘
cotθ and cosecθ are not defined at 0 .
∘

Variation of trigonometric ratios from 0 to 90 degrees

As θ increases from 0 to 90
∘
∘
• sinθ increases from 0 to 1
• cosθ decreases from 1 to 0

• tanθ increases from 0 to ∞

• cosecθ decreases from ∞ to 1

• secθ increases from 1 to ∞
• cotθ decreases from ∞ to 0