Show sin 67 degrees equals to cos 23 degreesThis is year 11 trigonometry. And yea I don't understand this question

Expert Answers
jeew-m eNotes educator| Certified Educator

sin67 = cos23

This is a true comment.

sin67 = 0.9205

cos23 = 0.9205

 

Usually if `alpha` is any small angle;

`sinalpha = cos(90-alpha)`

`cosalpha = sin(90-alpha)`

 

If `alpha = 67` then;

`90-alpha = 90-67 = 23`

rjtjain | Student

Consider a triangle ABC,

In which angle A=67, angle B=90 and angle C=23 (degrees)

Then, Sin A = sin 67 = BC/CA  (Since sine is ratio of :  side opposite to angle divided by hypotenuse)______(1)

Also Cos C = cos 23 = BC/CA (Since cosine is ratio of : Adjacent side divided by hypotenuse)______(2)

From (1) and (2) we can say that sin 67= cos 23 (Degrees).

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