You are here:
Calculus/calculus
Advertisement
Question
State the exact value, in simple radical form : (NO DECIMALS !!)
1. sin 225°
2. tan 3π/4
3. cos 270°
4. sin 11π/6
5. cos 150°
1. The sin(225°) can be found by noticing that 225° the same as 180°
+ 45°. Now the sin() is positive for the first 180° and negative for the second. The sin(225°) is just -sin(45°). A 45° angle has sides 1 and hypoteneuse root(2).
2. The tan(3π/4) can be found by knowing that π radians is 180°.
This make 3π/4 radians π/4 radians away from π radians.
The tan(3π/4) would be the same as -tan(π/4), which is -tan(45°).
We both know that is we have a 45° angle, the tan() is 1.
3. cos(270°): 270° is 90° + 180°, and the cos(90°) is 0,
so the cos(270°) is the same thing.
4. sin(11π/6): 11π/6 is the same as 12π/6 - π/6,
so the sin(11π/6) = sin(π/6)
since the sin() is reflective about π/2.
5. cos(150°): It can be seen that 150° is 180° - 30°,
so the cos(180°) is -cos(30°) since the cos(A) is the same as
-cos(180-A).
The cos(30°) is root(3)/2,
so the cos(150°) is just the negative of that.
Related Articles
Answers by Expert:
Scotto
Expertise
Any kind of calculus question you want. I also have answered some questions in Physics (mass, momentum, falling bodies), Chemistry (charge, reactions, symbols, molecules), and Biology.
Experience
Experience in the area: I have tutored students in all areas of mathematics for over 25 years.
Education/Credentials: BSand MS in Mathematics from Oregon State University, where I completed sophomore course in Physics and Chemistry. I received both degrees with high honors.
Awards and Honors: I have passed Actuarial tests 100, 110, and 135.
Publications
Maybe not a publication, but I have respond to well oveer 7,500 questions on the PC.
Well over 2,000 of them have been in calculus.
Education/Credentials
I aquired well over 40 hours of upper division courses. This was well over the number that were required.
I graduated with honors in both my BS and MS degree from Oregon State University.
I was allowed to jump into a few junior level courses my sophomore year.
Awards and Honors
I have been nominated as the expert of the month several times.
All of my scores right now are at least a 9.8 average (out of 10).
Past/Present Clients
My past clients have been students at OSU, students at the college in South Seattle, referals from a company, friends and aquantenances, people from my church, and people like you from all over the world.
©2012 About.com, a part of The New York Times Company. All rights reserved.