Question

Trig identity help !

Answer 1

\[\large (3sinx+cosx)^2+(sinx-3cosx)^2\]

Answer 2

=10

Answer 3

i dont understand how to expand

Answer 4

expanding \(\large (3sinx+cosx)^2 \) is the same as expanding \(\large (a+b)^2 \)
what's the problem?

Answer 5

use FOIL if u have to...

Answer 6

would it be 9sinx or 9sin^2x :S

Answer 7

that's what i dont uderstand

Answer 8

can u expand \(\large (3a+b)^2 \) = ????

Answer 9

\[\large 3x^2+3xy+y^2\]

Answer 10

no...

Answer 11

9x+3xy+y^2

Answer 12

no...

Answer 13

i cant get basic algebra right :/