Question

Math Analysis: Simplify each expressioncos^3 y + cos y*sin^2 y

Answer 1

well cos(y)sin(y) = 1/2sin(2y)

so you get cos^3(y) + 1/2sin(2y)

thats one possibility

an other is

cos(y) (cos^2(y) + sin(y)) = cos(y)(1 - sin^2(y) + sin(y))

don't know if there is a lot else you can do

Answer 2

the answer from the back of the book said cos y

Answer 3

so how would I get that

Answer 4

no idea...

Answer 5

...

Answer 6

not sure that's correct, but I may be wrong

Answer 7

for example: http://www.wolframalpha.com/input/?i=cos%5E3+45+%2B+cos+45*sin+45 and http://www.wolframalpha.com/input/?i=cos+45

Answer 8

(they are not the same)

Answer 9

Shouldn't it be \[\cos^3 y + \cos y \, \,\sin^2 y\],
because it would be easy to get cos y

Answer 10

yah

Answer 11

whoops i forgot to put the ^2 on the sin heheh ^^"

Answer 12

lol.... now that makes sense

its cos(y) (cos^2(y) + sin^2(y)) = cos(y) (1) since cos^2 + sin^2 = 1

answer cos(y)

Answer 13

it says cos^3 y in the equation not cos^2 y o-o

Answer 14

cos^3 y + cos Y*sin^2y

Answer 15

take cos(y) as a factor so cos(y) x cos^2(y) = cos^3(y)

Answer 16

i still dont get how the answer is cos y o-o

Answer 17

find the common factor between cos^3(y) + cos(y)sin^2(y) it is cos(y)

so you can factorise the expression to

\[\cos(y) \times (\cos^2 (y) + \sin^2(y))\]

Answer 18

cos y doesn't factor sin^2 y

Answer 19

ohh wait nvm i see now lol i feel like a fool now xD
Tyvm :3