Fenchurch
Badges: 0
#1
Report Thread starter 13 years ago
#1
Find, to 1 decimal place, the values of x in the interval −180° ≤ x ≤ 180° for which

a) cos (x + 40°) = 0.3,
b) 2 + tan 2x = 0.
0
reply
CalculusMan
Badges: 9
Rep:
?
#2
Report 13 years ago
#2
a) cos-1(0.3) will give you the '1st' value of cos. Then you can draw this value onto a quadrant diagram. The interval is -120 ≤ x + 40 ≤ 220.

Remember cos is positive, so values are in the 1st and 4th quadrants.

b) tan 2x = -2, -360 ≤ 2x ≤ 360 and then solve like in a)

Reply back if your still stuck, with the bits you dont understand.
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

University open days

  • Norwich University of the Arts
    Postgraduate Open Day Postgraduate
    Thu, 23 Jan '20
  • SOAS University of London
    Development Studies, Interdisciplinary Studies, Anthropology and Sociology, Languages, Cultures and Linguistics, Arts, Economics, Law, History, Religions and Philosophies, Politics and International Studies, Finance and Management, East Asian Languages & Cultures Postgraduate
    Sat, 25 Jan '20
  • University of Huddersfield
    Undergraduate Open Day Undergraduate
    Sat, 25 Jan '20

How many universities have you heard back from?

0 (91)
13.13%
1 (89)
12.84%
2 (89)
12.84%
19.05%
22.37%
19.77%

Watched Threads

View All