OpenStax, Algebra and Trigonometry 2e §9.2 Sum and Difference Identities · Exercise 21 · Trigonometry · Compound & multiple angles

Sum and Difference Identities · Exercise 21

Find the requested information.

Given that $s ina = \frac{4}{5},$ and $cos b = \frac{1}{3},$ with $a$ and $b$ both in the interval $[0, \frac{π}{2}),$ find $s in (a - b)$ and $cos (a + b) .$

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OpenStax, Algebra and Trigonometry 2e · §9.2 Sum and Difference Identities · Exercise 21

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