1. Prove result `sin(30)*cos(45)*tan(60)=sin(45)*cos(60)*cot(30)`Solution:LHS `=sin(30)cos(45)tan(60)`
`=(1/2)*(1/sqrt(2))*(sqrt(3))`
`=0.6124`
RHS `=sin(45)cos(60)cot(30)`
`=(1/sqrt(2))*(1/2)*(sqrt(3))`
`=0.6124`
Result is proved...
2. Prove result `2sin(30)+2tan(45)-3cos(60)-2cos^2(30)=0`Solution:LHS `=2sin(30)+2tan(45)-3cos(60)-2cos^2(30)`
`=2*(1/2)+2*(1)-3*(1/2)-2*((sqrt(3)/2)^2)`
`=1+2-1.5-1.5`
`=0`
`=`RHS
Result is proved...
3. Prove result `sin^2(50)+sin^2(40)=1`Solution:LHS `=sin^2(50)+sin^2(40)`
`sin(50)=cos(40)`
`sin(50)=sin(90-40)=cos(40)`
`=cos^2(40)+sin^2(40)`
`=1`
`=`RHS
`:.` Result is proved...
4. Prove result `sin(35)*sec(55)-cos(55)*csc(35)=tan(25)-cot(65)`Solution:LHS `=sin(35)sec(55)-cos(55)csc(35)`
`sec(55)=csc(35)` and `cos(55)=sin(35)`
`sec(55)=sec(90-35)=csc(35)`
`cos(55)=cos(90-35)=sin(35)`
`=sin(35)csc(35)-sin(35)csc(35)`
`=1-1`
`=0-> (1)`
RHS `=tan(25)-cot(65)`
`cot(65)=tan(25)`
`cot(65)=cot(90-25)=tan(25)`
`=tan(25)-tan(25)`
`=0-> (2)`
from (1) and (2)
Result is proved...
5. Prove result `tan(45)*sec(72)*sin(58)=cos(32)*csc(18)`Solution:LHS `=tan(45)sec(72)sin(58)`
`sec(72)=csc(18)` and `sin(58)=cos(32)`
`sec(72)=sec(90-18)=csc(18)`
`sin(58)=sin(90-32)=cos(32)`
`=1csc(18)cos(32)`
`=csc(18)cos(32)`
`=(1/(sin(18)))cos(32)`
`=csc(18)cos(32)`
`=`RHS
`:.` Result is proved...
6. Prove result `sin^2(34)-cot^2(46)-cos^2(56)+tan^2(44)=sec^2(62)-csc^2(28)`Solution:LHS `=sin^2(34)-cot^2(46)-cos^2(56)+tan^2(44)`
`cot(46)=tan(44)` and `cos(56)=sin(34)`
`cot(46)=cot(90-44)=tan(44)`
`cos(56)=cos(90-34)=sin(34)`
`=sin^2(34)-tan^2(44)-sin^2(34)+tan^2(44)`
`=0-> (1)`
RHS `=sec^2(62)-csc^2(28)`
`sec(62)=csc(28)`
`sec(62)=sec(90-28)=csc(28)`
`=csc^2(28)-csc^2(28)`
`=0-> (2)`
from (1) and (2)
Result is proved...
This material is intended as a summary. Use your textbook for detail explanation.
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