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Question
Sat July 07, 2012 By: Tabish

# value of sine and cosine

Sat July 07, 2012

Similarly, you can calculate the trigonometric ratio of angle 30 degrees. For finding trig ratios of angle 45 degrees, consider a isosceles right angled triangle.

For angle 0 degrees, proceed as follows:

Imagine an acute angle R of a right angle triangle reducing slowly to become zero. This can happen when PR slowly starts coinciding with QR, which results in reduction of side PQ to zero and PR becomes equal to QR. Therefore, Sin R, which is PQ/PR, becomes 0/PR, which is equal to 0 only.

So, sin00 = 0

Now, cos00 is equal to QR/PR.

As QR is the same as PR, therefore cos00 is equal to 1.

And tan00 = 0/1 which is 0

Therefore tan00 =0

For angle measuring 90 degrees, move R towards 90 degree angle Q.

Side QR becomes zero as PR coincides with PQ. Therefore,

SinR, which is PQ/PR becomes 1.

That is sin900 = 1

And cos900 R, which is QR/PR, becomes zero, as QR is zero.

That is cos00 =0

Now, tan900 is equal to 1/0, which is not defined. Therefore tan00 is not defined.
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