Algebra Examples

Evaluate cos(pi/4)^2-sin(pi/4)^2
cos2(π4)-sin2(π4)cos2(π4)sin2(π4)
Step 1
Apply the cosine double-angle identity.
cos(2π4)cos(2π4)
Step 2
Cancel the common factor of 22.
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Step 2.1
Factor 22 out of 44.
cos(2π2(2))cos(2π2(2))
Step 2.2
Cancel the common factor.
cos(2π22)
Step 2.3
Rewrite the expression.
cos(π2)
cos(π2)
Step 3
The exact value of cos(π2) is 0.
0
 [x2  12  π  xdx ]