- #1
MrGoATi
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Mentor note: Moved thread to homework section
ok So I'm doing supposedly easy trigonometry problems. i did the easiest ones. now I have no idea how to solve 2.
first one is count
sin+cos
When
tg - (1/tg) = -(7/12)
what i figured is that i probably need to use (sin/cos) - (cos/sin) = -7/12
but i came empty after 30 minutes of playing with both formulas.
The ASNWER is supposed to be 1.4
************
the other problem is prove:
cosx^2=siny*cosy
when
cos(π+2x)=2sin^2(π/4-y)
the second formula I made into
cos(2x)=2cos^2(y)
then used cos(2x) = 2cos^2(x) -1
cosx^2 = ( 2cos^2(y)+1 ) / 2
if all that's correct. Then it made it possible to connect both formulas leaving just y.
( 2cos^2(y)+1 ) / 2 = siny*cosy
but i can only go in circles here
ok So I'm doing supposedly easy trigonometry problems. i did the easiest ones. now I have no idea how to solve 2.
first one is count
sin+cos
When
tg - (1/tg) = -(7/12)
what i figured is that i probably need to use (sin/cos) - (cos/sin) = -7/12
but i came empty after 30 minutes of playing with both formulas.
The ASNWER is supposed to be 1.4
************
the other problem is prove:
cosx^2=siny*cosy
when
cos(π+2x)=2sin^2(π/4-y)
the second formula I made into
cos(2x)=2cos^2(y)
then used cos(2x) = 2cos^2(x) -1
cosx^2 = ( 2cos^2(y)+1 ) / 2
if all that's correct. Then it made it possible to connect both formulas leaving just y.
( 2cos^2(y)+1 ) / 2 = siny*cosy
but i can only go in circles here
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