Question

Without using trigonometric table , prove that: sec 70° sin 20° + cos 70° = 2
Answer :-
= sec (90°-20) sin 20° + cos 20° cosec (90°-20)=2
= cosec 20° sin 20° + cos 20° sec 20°
= 1/sin 20° .sin 20 + cos 20° .1/cos 20°
= 1 + 1
= 2 ​

Answer 1

Answer:

Step-by-step explanation:

778

Answer 2

Step-by-step explanation:

= sec (90°-20) sin 20° + cos 20° cosec (90°-20)=2

= cosec 20° sin 20° + cos 20° sec 20°

= 1/sin 20° .sin 20 + cos 20° .1/cos 20°

= 1 + 1

= 2