Why does my child mix up sin 30° and cos 30°?
Your child mixes up sine and cosine's exact values, such as sin 30° as √3/2 instead of 1/2.
Why children do it
The values 1/2 and √3/2 come up for both angles, so they're easy to swap. Drawing the triangle with angles 30°, 60° and 90°, sides 1, √3 and 2, and reading the ratio from the angle in the question, settles it: sin 30° = 1/2 and cos 30° = √3/2.
How to help at home
Ask them to draw the 30°, 60°, 90° triangle and read each ratio from the angle in the question.
The right way
What is the exact value of sin 30°?
- 1/2In the 30°, 60°, 90° triangle, opposite 30° is 1 and the hypotenuse is 2.
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