Question

solve the following problems with explanation.​

Answer 1

Step-by-step explanation:

(i) Sin20° = Cos(90°-20°) = Cos70°

(ii) tan30° = Cot(90°-30°) = Cot60° = 1/tan60°

tan30° × tan60° = 1

(iii) Cos40° = Sin(90°-40°)= Sin50°

Answer 2

Step-by-step explanation:

Here,

$i) \sin(20) \\ = \cos(90 - 20) \\ = \cos(70)$

then,

$ii) \: \tan(30) \times \tan(60) = 1$

as

$\tan(30) = \frac{1}{ \sqrt{3} } \\ and \: \tan(60) = \sqrt{3}$

therefore,

$iii) \: \cos(40) \\ = \sin(90 - 40) \\ = \sin(50)$

this is the required answer...

hope this help u...