1. Angle α lies in quadrant II , and tanα=−12/5 . Angle β lies in quadrant IV , and cosβ=3/5 .

What is the exact value of cos(α+β) ?

Enter your answer in the box.

cos(α+β) =

Second question deleted by Melody.

One question per post and see if you can learn from the first answer before you post the second question.

jjennylove Mar 11, 2020

#1**0 **

1. Angle α lies in quadrant II , and tanα=−12/5 . Angle β lies in quadrant IV , and cosβ=3/5 .

What is the exact value of cos(α+β) ?

Enter your answer in the box.

Remember that

sin(angle) is the y value over the hypotenuse.

cos(angle) is the x value over the hypotenuse.

\(tan(angle)=\frac{sin(angle)}{cos(angle)}=\frac{y}{x}\)

Here is a pic that should help:

and

\( cos(\alpha+\beta)=cos\alpha cos\beta - sin\alpha sin\beta \\ \)

Now see if you can work it out yourself. :)

Melody Mar 11, 2020