SOLUTION: I need help with a couple of problems: 1. Evaluate: {{{3(cos7pi/6) + 2 cos(-5pi/3)}}} 2. Evaluate: {{{4tan(-3pi/4) + sin(-pi/4)}}}

Algebra ->  Finance -> SOLUTION: I need help with a couple of problems: 1. Evaluate: {{{3(cos7pi/6) + 2 cos(-5pi/3)}}} 2. Evaluate: {{{4tan(-3pi/4) + sin(-pi/4)}}}      Log On


   

Question 984781: I need help with a couple of problems:
1. Evaluate: 3%28cos7pi%2F6%29+%2B+2+cos%28-5pi%2F3%29
2. Evaluate: 4tan%28-3pi%2F4%29+%2B+sin%28-pi%2F4%29
Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!

1.  3%28cos7pi%2F6%29 + 2cos%28-5pi%2F3%29 = 3*cos(7*30°) + 2*cos(-5*60°) = 3*cos(210°) + 2*cos(-300°) = -3*cos(30°) + 2*cos(60°) = -3%2A%28sqrt%283%29%2F2%29 + 2%2A%281%2F2%29 = -3sqrt%283%29%2F2 + 1.

2.  4tan%28-3pi%2F4%29+%2B+sin%28-pi%2F4%29 = 4*tan(-3*45°) + sin(-45°) = 4*tan(45°) - sin(45°) = 4%2A1 - sqrt%282%29%2F2 = 4+-+sqrt%282%29%2F2.

It is so simple . . .