Write the Expression in Terms of Sine and Cosine, and Simplify

question 266

Multiple Choice

Write the expression in terms of sine and cosine, and simplify so that no quotients appear in the final expression.
-Find $\cos ( \mathrm { s } - \mathrm { t } )$ given that $\cos \mathrm { s } = - \frac { 12 } { 13 }$ , with $\mathrm { s }$ in quadrant II, and $\sin t = \frac { 8 } { 17 }$ , with $\mathrm { t }$ in quadrant II.

• A) \(- \frac { 220 } { 221 }\)
• B) \(\frac { 140 } { 221 }\)
• C) \(\frac { 220 } { 221 }\)
• D) \(- \frac { 140 } { 221 }\)

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Definitions:

Placebo

A substance with no therapeutic effect, used as a control in testing new drugs, or used to stimulate a patient's psychological healing process.

StdDev

Standard Deviation, a measure of the amount of variation or dispersion in a set of values.

Median

The central number in a series that divides the upper half from the bottom half.

StdDev

A rephrased term for standard deviation, indicating the degree to which individual data points in a set diverge from the mean value.