# Pre Calc

posted by .

evaluate the trigonometric function of the given quadrantal angle.

tan 1400°
cos 9π
cos 13π/2
sin (-17π)

• Pre Calc -

subtract multiple of 360° (1400/360 = 3.8..
so
tan 1400°
= tan320° , 320 is in IV and 40° from the x-axis
= -tan40
= ....

cos 9π
= cos π , (took away 4 multiples of 2π)
= -1

cos 13π/2
= cos π/2 (took away 6π)
= 0

sin(-17π)
= sin(-17π + 18π) , ( I added 9 rotations)
= sin π
= 0

## Similar Questions

1. ### Math

Evaluate *Note - We have to find the exact value of these. That I know to do. For example sin5π/12 will be broken into sin (π/6) + (π/4) So... sin 5π/12 sin (π/6) + (π/4) sin π/6 cos π/4 + cos …
2. ### Math 2nd question

Express as a single sine or cosine function (note: this is using double angle formulas) g) 8sin^2x-4 I just don't get this one. I know it's got something to do with the 1-2sin^2x double angle formula. It's the opposite though?
3. ### Math integrals

What is the indefinite integral of ∫ [sin (π/x)]/ x^2] dx ?
4. ### pre calc

evaluate the trigonometric function of the given quadrantal angle. tan 1440° Evaluate without using ratios in reference triangle. sec 3π/4
5. ### Precalculus

Use one of the identities cos(t + 2πk) = cos t or sin(t + 2πk) = sin t to evaluate each expression. (Enter your answers in exact form.) (a) sin(19π/4) (b) sin(−19π/4) (c) cos(11π) (d) cos(53π/4) …
6. ### Trig Help!

Question: Trying to find cos π/12, if cos π/6 = square root 3 over 2, how to find cos π/12 using DOUBLE angle formula?
7. ### product of function

Given: f(x)=2 cos x and g(x)=sin x. Which of these expressions is equivalent to (fxg)(π/16)?
8. ### Trigonometry

How do I evaluate the trigonometric functions of the quadratic angle?