Question

HELP

Prove: cos θ - cosθ •sin^2 θ = cos^3 θ. You must show all work.

I understand how to do this problem kind of..but ive looked up a ton of different things and they simplified it to cosθ(1-sin^2θ)=cos^3θ

How did they simplify that???

Answer 1

@phi @amistre64

Answer 2

those are all exponents in the equation btw

Answer 3

post it correctly notated

Answer 4

think i fixed it..

Answer 5

a - ab = c

how would you simplify it?

Answer 6

distributive property?

Answer 7

and what is our basic trig identity? the pythagorean one

Answer 8

sin^2θ+cos^2θ=1

Answer 9

well, an undistributive property so yeah

a(1-b) = c

good, so 1-sin^2 = what?

Answer 10

cos^θ

Answer 11

cos^2θ sorry

Answer 12

then we are simplified

show me the work

Answer 13

using a(1-b)=c all you really have to do is place the values for a, b and c into the equation, right? So then it'd come out as cosθ(1-sin^2θ)=cos^3θ...which can be simplified into cosθ(cos^2θ) which is equal to cos^3θ

Answer 14

very good

Answer 15

thanks so much!!