5. The Sine and Cosine Ratios
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The cosine of an acute angle is equal to the sine of its complement.
sin 31^(∘)
The cosine of an acute angle is equal to the sine of its complement. |
Keep in mind that complementary angles add up to 90^(∘). To find the complement of 59, we subtract our given angle from 90. Now, we can rewrite cos 59^(∘) in terms of sine. cos 59^(∘) = sin(90^(∘)-59^(∘)) = sin 31^(∘)