Posted by Greg on Monday, October 8, 2012 at 9:03am.
You should be able to make a quick sketch of the following right-angled triangles
30° - 60° - 90° ---> π/6rad - π/3rad - π/2 ---> 1 -- √3 -- 2
and
45° - 45° - 90° --> π/4 - π/4 - π/2 ---> 1 - 1 - √2
You should also know the CAST rule, that is, where are each of the basic trig functions + or -
I will do the second one for you
tan (7π/6)
If it helps you, let's do in degrees.
7π/6 = 7(π/6) = 7(30°) = 210°
Now 210° is in quad III and 30 from the x-axis
we know from the above triangles that
tan 30° = 1/√3
so in the third quadrant, by CAST, the tangent is positive,
thus tan 7π/6 = 1/√3
( you can of course check all your answers with a calculator)
do the others the same way
Related Questions
Precalculus/Trig 6 - Find the exact value of the following trigonometric ...
PreCalculus - Hi I need some assistance on this problem find the exact value do ...
Math - Use an addition or subtraction formula to write the expression as a ...
trig - please help me. use trig. identities to find the exact value. tan 25°...
trig - please help me. use trig. identities to find the exact value. tan 25°...
trig - Solve the equation for cos theta-tan theta=0 for greater than or egual to...
Trigonometry - Find the exact value of tan(a-b) sin a = 4/5, -3pi/2<a&...
math - Use the exact values of the sin, cos and tan of pi/3 and pi/6, and the ...
math - Use the exact values of the sin, cos and tan of pi/3 and pi/6, and the ...
Math - Could someone explain the steps for this question. Simplify the ...
For Further Reading
