# What is the right choice for question 37) ? http://postimg.org/image/9ikm61h8f/

### 1 Answer | Add Yours

The CAST rule applies to the positive values of functions in the xy-plane. **C** starts in quadrant 4 therefore only the **cosine** is **positive** in quadrant **IV**. AST moves in the counterclockwise direction for each quadrant. A is in quadrant I which indicates ALL (sine,cosine, and tangent) are positive in quadrant I, S is quadrant II which indicates only the sine is positive in quadrant II, and **T** indicating **tangent** is **positive** in **quadrant** **III**.

**Therefore the CAST rule applies to choice: "d"**

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