1.

Using the trigonometric table and evalute (a) `sin^(2)45^(@)+cos^(2)45^(@)` (b) `sec^(2)30^(@)-tan^(2)30^(@)`

Answer» (a) `sin^(2) 45^(@)+cos^(2)45^(@)`
`=((1)/(sqrt(2)))^(2)+((1)/(sqrt(2)))^(2)`
`=(1)/(2)+(1)/(2)=1`
Hence, `sin^(2)45^(@)+cos^(2)45^(@)=1`
(b) `sec^(2)30^(@)- tan^(2)30^(@)`
`=((2)/(sqrt(3)))^(2)-((1)/(sqrt(3)))^(2)`
`=(4)/(3)-(1)/(3)=(3)/(3)=1`
Hence , `sec^(2)30^(@)-tan^(2)30^(@)=1`


Discussion

No Comment Found