Precalculus (6th Edition) Blitzer

Published by Pearson
ISBN 10: 0-13446-914-3
ISBN 13: 978-0-13446-914-0

Chapter 5 - Section 5.2 - Sum and Difference Formulas - Exercise Set - Page 671: 96


The statement does not make sense.

Work Step by Step

The provided statement does not make complete sense because using the sum and difference formulas one can truly calculate the exact value for the known angles like $15{}^\circ ,30{}^\circ ,45{}^\circ ,60{}^\circ ,105{}^\circ $. But suppose there is a need to find the value of $\sin \left( 60{}^\circ +1{}^\circ \right)\text{or}\sin \left( 90{}^\circ -29{}^\circ \right)$ but the exact value of the trigonometric functions for $1{}^\circ \text{or }29{}^\circ $ is not exactly known. Hence, the exact value cannot be calculated.
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