Post Your Problem Here (1 Viewer)

[FinalFantasy]

Hi i was wonderin if sum1 could do this question for me:
Find the exact value of sin(13 pi/12)

thx

sin(13pi\12)=sin 195=-sin 15=-sin(60-45)=-(sin60cos45-cos60sin45)
then u can do it

 

[taco man]

thx man, i am so stupid i didnt c that

 

[taco man]

sry to bother every1 again but heres a another question:
Prove: sin(A+B)/cos(A-B)=tanA+tanB/1+(tanA)(tanB)

thx

 

[FinalFantasy]

sry to bother every1 again but heres a another question:
Prove: sin(A+B)/cos(A-B)=tanA+tanB/1+(tanA)(tanB)

thx

LHS=sin(A+B)/cos(A-B)=(sinAcosB+cosAsinB)\(cosAcosB+sinAsinB)
RHS=tanA+tanB/1+(tanA)(tanB)
=[(sinA\cosA)+(sinB\cosB)]\[1+(sinA\cosA)(sinB\cosB)]
=(sinAcosB+cosAsinB)\(cosAcosB) \ (cosAcosB+sinAsinB)\cosAcosB
=sinAcosB+cosAsinB\cosAcosB+sinAsinB
=LHS

 

[taco man]

Hey just wonderin why is the graph of -tan^(-1) (1-x)----(1-x is not a power) is shifted left , shouldnt it be it shifted right 1 units left since -x+1?

 

[mojako]

Hey just wonderin why is the graph of -tan^(-1) (1-x)----(1-x is not a power) is shifted left , shouldnt it be it shifted right 1 units left since -x+1?

tan^(-1) (x+1) is tan^(-1) (x) shifted left by 1 unit.
-tan^(-1) (1-x) is -tan^(-1) (-x) shifted left by 1 unit.