TRIG 1

Given that Sin Ө  = ¹/10, Find Cos Ө.

Solution

Sin²Ө + Cos²Ө = 1

(¹/10)² + Cos²Ө = 1

Cos²Ө = 1 - (¹/10)²

Cos²Ө = 1 - ¹/100

Cos²Ө =¹⁰⁰/100 - ¹/100

Cos²Ө = ⁹⁹/100

√Cos²Ө = √(⁹⁹/100)       keeping under radical sign both sides

CosӨ =  √(⁹⁹/100)

CosӨ =  √99      since √100=10

                10

CosӨ =  √(3x3x11)     

                 10

CosӨ =  3√(11)     

                 10

CosӨ =  3√11      answer

                 10

  

TRY THIS………

Given that Sin Ө  = ¹/7, Find Cos Ө.