# Thread: Trig Equation & Expression

1. ## Trig Equation & Expression

hi guys im having a bit of trouble with this 2 questions from my text book.

1. Find the exact value of the expression:

cos(arctan3/4)+tan(arccos3/5)

2. Solve the trig Eq:

2cos^3(x)+5cos^2(x)=2-cos(x)

can you guy please post a worked solution if you can im out of ideas.

thanks

2. ## Re: Trig Equation & Expression

For the first 1 draw the triangle(to understand) and then use your calculator

and for the second
2cos^3(x)+5cos^2(x)=2-cos(x)

--> 2cos^3(x)+5cos^2(x)+cos(x)-2=0

factorize and then solve for x...

3. ## Re: Trig Equation & Expression

Going to need more help then that

4. ## Re: Trig Equation & Expression

Show me what you have tried to do or what you don't understand and then we can take it from there....