Use the Cofunction Identities to Evaluate the Expression Without Using $\sin ^ { 2 } 40 ^ { \circ } + \sin ^ { 2 } 50 ^ { \circ }$

Short Answer

Use the cofunction identities to evaluate the expression without using a calculator.
​ $\sin ^ { 2 } 40 ^ { \circ } + \sin ^ { 2 } 50 ^ { \circ }$ ​