Can you solve the given problems?

Here are some math problems i need help solving... ive been trying to solve ones like these but just dont undersand it and my brain completely turned off from about a billion others like these.

1.The perimiter of a circle equals 6 pi, what is the area of the circle?

2. A race track has 1km, a bike weel has a radius of .5 m. How many turns does the wheel have to make to go around the track?

3. Simplify:
(1-sin^2 a)
over =
1- cos^2 a

4. Simplify:
tg a * cos a

5.Simplify:
1 + tg^2 a

6.Simplify:
(1 - sin a) * (1+sin a)
OVER
(sin a) * (cos a)

7. Solve:
tg 60
OVER - sqrt of 3
ctg 45 - sin 30

8. Solve:
sin 30 + cos^2 45
OVER
2 - tg 45

9. Solve:
4 cos 60 - 3tg^2 30
OVER - ctg 45
sin 45 * cos 45

10. Solve:
sin 30 * cos 30 * tg 30 * ctg 30

I am doing a few for you.You may contact me through yahoo Answers when you require solutions of many a problems
tg a*cosa
=(sin a/cosa)cosa
sin a
5.1+tg^2a
=1+(sin^2a/cos^2a)
=(cos^2a+sin^2a)/cos^2a
=1/cos^a
=sec^2a
6.Numerator=(1+sin a)(1-sin a)
=1-sin^2a [applying (a+b)(a-b)=a^2-b^2 formula]
=cos^2 a
Numertor/denominator
=cos^2a/sina*cosa
=cos a/sin a
=cot a

I know the answers to all...
but..you know what...its called homework...if you dont do it yourself..you will never learn..and you will fail your math test...maybe you could ask your teacher to help you with them?
1. Perimeter = 2*PI*radius 6*PI = means radius = 3
2. 1000/PI
3. cos^2a/sin^2a

I'm not up on my trig identities any more. Start from the definition of tangent and remember that sin^2a = 1 - cos^2a and vice versa.
4. tg a * cos a = tan(a)*cos(a) = sin(a)/cos(a) * cos(a) = sin(a)

5. 1 + tan^2(a) = 1 + sin^2(a)/cos^2(a) = [cos^2(a) + sin^2(a)]/cos^2(a) = 1/cos^2(a) = csc^2(a)

6. {(1 - sin a) * (1+sin a)}/{(sin a) * (cos a)}
(1 - sin a) * (1+sin a) = 1 - sin^2(a), but remember that sin^2(a) + cos^2(a) = 1, therefore, 1-sin^2(a) = cos^2(a)

cos^2(a)/sina*cosa = cos(a)/sin(a) = cot(a)

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Cycling Bike Race Bike Insurance Bike Repair Bicycle Shop Bike Tours Trail Map

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