In Exercises 31–38, find a cofunction with the same value as the ...

Question

In Exercises 31–38, find a cofunction with the same value as the given expression.

sin 7°

Accepted Answer

Hello everybody. I hope you're doing tonight today. Today we're going to blog at this question that states which of the following core functions has the same value as sine of 11.5 degrees where the answer choices are a cosine of 78.5 degrees. B cosine of 11.5 degrees. C cosine of 23 degrees and the cosine of 168.5 degrees. Now, we know that sine and cosine are co functions of each other. So now we need to know a rule on how we can switch between them and how we can equate each, each of them to each other. And that will be that sign of theta will be equal to cosine of open parentheses, 90 minus a theta. And that is how you can equate sign and cosine. So now we can plug in our, our values and we'll have that sign of 11.5 degrees is equal to cosine of open parentheses, 90 degrees minus 11.5 degrees. And now we can focus on the cosine side since that's the part that we care about now and we can just plug in 90 minus 7.5 into our calculator or just calculate it by hand. And we'll have that sine of 11.5 degrees is equal to cosine of 78.5 degrees. And just like that by using this simple rule on how to equate sine and cosine, we see that answer choice. A will be the best answer for this question. So I hope that was helpful. And until next time.

In Exercises 31–38, find a cofunction with the same value as the given expression. sin 7°

Key Concepts

Cofunction Identities

Complementary Angles

Trigonometric Functions

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