Question

In triangle ABC, right angled at B, if $\angle A$ is made smaller and smaller till it becomes zero, find the value of Sin A and Cos A.

• A. 0, 1
• B. 0, √3
• C. 0, Not defined
• D. Not defined, 0

Answer 1

The correct option is A

0, 1

∠A gets smaller and smaller, the length of the side BC decreases. The point C gets closer to point B and finally ∠A becomes very close to zero. AC becomes almost the same as AB.

When BC gets very close to zero the value of Sin A = BC/AC is very close to zero and AC becomes equal to AB which makes cos A = AB/AC becomes close to 1

So, When A= 0^o, we define Sin0^o = 0

Cos A = Cos 0^o = .1

With sin and cos ratios of 0⁰ known , other ratios can be easily determined